Guess the number/With feedback (player): Difference between revisions
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let buf: &mut [u8] = [0u8, ..8]; |
let buf: &mut [u8] = [0u8, ..8]; |
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let num_bytes = stdin.read(buf); |
let num_bytes = stdin.read(buf); |
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let answer = str:: |
let answer = str::from_utf8(buf).slice_to(num_bytes.unwrap()).trim(); |
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match answer { |
match answer { |
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"e" | "E" => { |
"e" | "E" => { |
Revision as of 12:38, 7 January 2014
You are encouraged to solve this task according to the task description, using any language you may know.
The task is to write a player for the game that follows the following rules:
- The scorer will choose a number between set limits. The computer player will print a guess of the target number. The computer asks for a score of whether its guess is higher than, lower than, or equal to the target. The computer guesses, and the scorer scores, in turn, until the computer correctly guesses the target number.
The computer should guess intelligently based on the accumulated scores given. One way is to use a Binary search based algorithm.
- Cf.
Ada
<lang Ada>with Ada.Text_IO; procedure Guess_Number_Player is
procedure Guess_Number (Lower_Limit : Integer; Upper_Limit : Integer) is type Feedback is (Lower, Higher, Correct); package Feedback_IO is new Ada.Text_IO.Enumeration_IO (Feedback); My_Guess : Integer := Lower_Limit + (Upper_Limit - Lower_Limit) / 2; Your_Feedback : Feedback; begin Ada.Text_IO.Put_Line ("Think of a number!"); loop Ada.Text_IO.Put_Line ("My guess: " & Integer'Image (My_Guess)); Ada.Text_IO.Put ("Your answer (lower, higher, correct): "); Feedback_IO.Get (Your_Feedback); exit when Your_Feedback = Correct; if Your_Feedback = Lower then My_Guess := Lower_Limit + (My_Guess - Lower_Limit) / 2; else My_Guess := My_Guess + (Upper_Limit - My_Guess) / 2; end if; end loop; Ada.Text_IO.Put_Line ("I guessed well!"); end Guess_Number; package Int_IO is new Ada.Text_IO.Integer_IO (Integer); Lower_Limit : Integer; Upper_Limit : Integer;
begin
loop Ada.Text_IO.Put ("Lower Limit: "); Int_IO.Get (Lower_Limit); Ada.Text_IO.Put ("Upper Limit: "); Int_IO.Get (Upper_Limit); exit when Lower_Limit < Upper_Limit; Ada.Text_IO.Put_Line ("Lower limit must be lower!"); end loop; Guess_Number (Lower_Limit, Upper_Limit);
end Guess_Number_Player;</lang>
AutoHotkey
Works with the AutoHotkey entry at: Guess the number/With feedback
<lang AutoHotkey>MaxGuesses = 50
GetParams(LowerBound,UpperBound) If Not GuessNum(LowerBound,UpperBound,MaxGuesses)
MsgBox, 16, Error, Could not guess number within %MaxGuesses% guesses.
GetParams(ByRef LowerBound,ByRef UpperBound) {
WinWait, Number Guessing ahk_class #32770 Sleep, 100 WinGet, InputID, ID ControlGetText, Temp1, Static1, ahk_id %InputID% Temp2 := InStr(Temp1,A_Space,False,32) LowerBound := SubStr(Temp1,31,Temp2 - 31) UpperBound := SubStr(Temp1,Temp2 + 5,-1)
}
GuessNum(LowerBound,UpperBound,MaxGuesses) {
Loop, %MaxGuesses% { Guess := LowerBound + ((UpperBound - LowerBound) // 2) Temp1 := SendGuess(Guess) ToolTip % Temp1 If Temp1 = Too Low LowerBound = %Guess% Else If Temp1 = Too High UpperBound = %Guess% Else Return, 1 }
}
SendGuess(Guess) {
WinGet, InputID, ID, Number Guessing ahk_class #32770 ControlSetText, Edit1, %Guess%, ahk_id %InputID% ControlSend, Button1, {Enter}, ahk_id %InputID% Loop { Sleep, 50 IfWinExist, Correct ahk_class #32770 Return Else IfWinExist, Incorrect ahk_class #32770 Break } ControlGetText, Temp1, Static2 WinClose WinWaitClose IfInString, Temp1, low Return, "Too Low" Else Return, "Too High"
}</lang>
BBC BASIC
<lang bbcbasic> min% = 1
max% = 100 PRINT "Think of a number between "; min% " and " ;max% PRINT "I will try to guess your number." REPEAT guess% = (min% + max%) DIV 2 PRINT "My guess is " ; guess% INPUT "Is it higher than, lower than or equal to your number", answer$ CASE LEFT$(answer$,1) OF WHEN "L","l": min% = guess% + 1 WHEN "H","h": max% = guess% - 1 WHEN "E","e": EXIT REPEAT OTHERWISE: PRINT "Sorry, I didn't understand your answer." ENDCASE UNTIL FALSE PRINT "Goodbye." END</lang>
C
<lang C>#include <stdio.h>
int main(){
int bounds[ 2 ] = {1, 100}; char input[ 2 ] = " "; /* second char is for the newline from hitting [return] */ int choice = (bounds[ 0 ] + bounds[ 1 ]) / 2; /* using a binary search */
printf( "Choose a number between %d and %d.\n", bounds[ 0 ], bounds[ 1 ] );
do{ switch( input[ 0 ] ){ case 'H': bounds[ 1 ] = choice; break; case 'L': bounds[ 0 ] = choice; break; case 'Y': printf( "\nAwwwright\n" ); return 0; } choice = (bounds[ 0 ] + bounds[ 1 ]) / 2;
printf( "Is the number %d? (Y/H/L) ", choice ); }while( scanf( "%1s", input ) == 1 );
return 0;
}</lang>
Demonstration (number is 57):
Choose a number between 1 and 100. Is the number 50? (Y/H/L) L Is the number 75? (Y/H/L) H Is the number 62? (Y/H/L) H Is the number 56? (Y/H/L) L Is the number 59? (Y/H/L) H Is the number 57? (Y/H/L) Y Awwwright
The following is a hacky solution using bsearch() and pointers to represent integers. Although the pointers do not point to valid things, bsearch() doesn't actually dereference the pointers or care what they point to; it just passes them to the comparator and searches the space of pointers. We can use that to search any space of integers.
<lang c>#include <stdio.h>
- include <stdlib.h>
- include <ctype.h>
enum {
LOWER = 0, UPPER = 100, KEY = LOWER-1 // some value that is not in the valid range
};
char dummy; // A pointer to represent the integer 0, and the basis of our integer-as-pointer // representation. We can't use the null pointer because bsearch() returns that // for not found.
- define ZERO ((void *)&dummy)
int get_value(int x) {
if (x == KEY) return 0; printf("My guess is: %d. Is it too high, too low, or correct? (H/L/C) ", x); char input[2] = " "; scanf("%1s", input); switch (tolower(input[0])) { case 'l': return -1; case 'h': return 1; case 'c': return 0; } fprintf(stderr, "Invalid input\n"); exit(1); return 0;
}
int my_cmp(const void *x, const void *y) {
return get_value(x - ZERO) - get_value(y - ZERO);
}
int main() {
printf("Instructions:\n"
"Think of integer number from %d (inclusive) to %d (exclusive) and\n" "I will guess it. After each guess, you respond with L, H, or C depending\n" "on if my guess was too low, too high, or correct.\n", LOWER, UPPER);
void *result = bsearch(ZERO + KEY, ZERO + LOWER, UPPER-LOWER, 1, my_cmp); if (result == NULL) fprintf(stderr, "That is impossible.\n"); else printf("Your number is %d.\n", (int)(result - ZERO)); return 0;
}</lang>
C++
A clever solution that takes advantage of C++'s built-in binary search function lower_bound()
. Instead of searching a slice of a container, we search a range of numbers by implementing a specially-designed custom iterator.
<lang cpp>#include <iostream>
- include <algorithm>
- include <string>
- include <iterator>
struct GuessNumberIterator : std::iterator<std::random_access_iterator_tag, int> {
int i; GuessNumberIterator() { } GuessNumberIterator(int _i) : i(_i) { } GuessNumberIterator& operator++() { ++i; return *this; } GuessNumberIterator operator++(int) { GuessNumberIterator tmp = *this; ++(*this); return tmp; } bool operator==(const GuessNumberIterator& y) { return i == y.i; } bool operator!=(const GuessNumberIterator& y) { return i != y.i; } int operator*() { std::cout << "Is your number less than or equal to " << i << "? "; std::string s; std::cin >> s; return (s != "" && (s[0] == 'y' || s[0] == 'Y')) ? 0 : -1; } GuessNumberIterator& operator--() { --i; return *this; } GuessNumberIterator operator--(int) { GuessNumberIterator tmp = *this; --(*this); return tmp; } GuessNumberIterator& operator+=(int n) { i += n; return *this; } GuessNumberIterator& operator-=(int n) { i -= n; return *this; } GuessNumberIterator operator+(int n) { GuessNumberIterator tmp = *this; return tmp += n; } GuessNumberIterator operator-(int n) { GuessNumberIterator tmp = *this; return tmp -= n; } int operator-(const GuessNumberIterator &y) { return i - y.i; } int operator[](int n) { return *(*this + n); } bool operator<(const GuessNumberIterator &y) { return i < y.i; } bool operator>(const GuessNumberIterator &y) { return i > y.i; } bool operator<=(const GuessNumberIterator &y) { return i <= y.i; } bool operator>=(const GuessNumberIterator &y) { return i >= y.i; }
}; inline GuessNumberIterator operator+(int n, GuessNumberIterator &i) { return i + n; }
const int lower = 0; const int upper = 100;
int main() {
std::cout << "Instructions:\n"
<< "Think of integer number from " << lower << " (inclusive) to " << upper << " (exclusive) and\n" << "I will guess it. After each guess, I will ask you if it is less than\n" << "or equal to some number, and you will respond with \"yes\" or \"no\".\n";
int answer = std::lower_bound(GuessNumberIterator(lower), GuessNumberIterator(upper), 0).i; std::cout << "Your number is " << answer << ".\n"; return 0;
}</lang>
C#
<lang csharp>using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading; //Remember to add this if you want the game to pause in RealisticGuess.Start()
namespace ConsoleApplication1 {
class RealisticGuess //Simulates a guessing game between two people. Guessing efficiency is not a goal. { private int max; private int min; private int guess;
public void Start() { Console.Clear(); string input;
try { Console.WriteLine("Please enter the lower boundary"); input = Console.ReadLine(); min = Convert.ToInt32(input); Console.WriteLine("Please enter the upper boundary"); input = Console.ReadLine(); max = Convert.ToInt32(input); } catch (FormatException) { Console.WriteLine("The entry you have made is invalid. Please make sure your entry is an integer and try again."); Console.ReadKey(true); Start(); } Console.WriteLine("Think of a number between {0} and {1}.", min, max); Thread.Sleep(2500); Console.WriteLine("Ready?"); Console.WriteLine("Press any key to begin."); Console.ReadKey(true); Guess(min, max); } public void Guess(int min, int max) { int counter = 1; string userAnswer; bool correct = false; Random rand = new Random();
while (correct == false) { guess = rand.Next(min, max); Console.Clear(); Console.WriteLine("{0}", guess); Console.WriteLine("Is this number correct? {Y/N}"); userAnswer = Console.ReadLine(); if (userAnswer != "y" && userAnswer != "Y" && userAnswer != "n" && userAnswer != "N") { Console.WriteLine("Your entry is invalid. Please enter either 'Y' or 'N'"); Console.WriteLine("Is the number correct? {Y/N}"); userAnswer = Console.ReadLine(); } if (userAnswer == "y" || userAnswer == "Y") { correct = true; } if (userAnswer == "n" || userAnswer == "N") { counter++; if (max == min) { Console.WriteLine("Error: Range Intersect. Press enter to restart the game."); //This message should never pop up if the user enters good data. Console.ReadKey(true); //It handles the game-breaking exception that occurs Guess(1, 101); //when the max guess number is the same as the min number. } Console.WriteLine("Is the number you're thinking of lower or higher? {L/H}"); userAnswer = Console.ReadLine(); if (userAnswer != "l" && userAnswer != "L" && userAnswer != "h" && userAnswer != "H") { Console.WriteLine("Your entry is invalid. Please enter either 'L' or 'H'"); Console.WriteLine("Is the number you're thinking of lower or higher? {L/H}"); userAnswer = Console.ReadLine(); } if (userAnswer == "l" || userAnswer == "L") { max = guess; } if (userAnswer == "h" || userAnswer == "H") { min = guess; } } } if (correct == true) { EndAndLoop(counter); } }
public void EndAndLoop(int iterations) { string userChoice; bool loop = false; Console.WriteLine("Game over. It took {0} guesses to find the number.", iterations); while (loop == false) { Console.WriteLine("Would you like to play again? {Y/N}"); userChoice = Console.ReadLine(); if (userChoice != "Y" && userChoice != "y" && userChoice != "N" && userChoice != "n") { Console.WriteLine("Sorry, your input is invalid. Please answer 'Y' to play again, or 'N' to quit."); } if (userChoice == "Y" || userChoice == "y") { Start(); } if (userChoice == "N" || userChoice == "n") { Environment.Exit(1); } } } } class Program { static void Main(string[] args) { Console.Title = "Random Number"; RealisticGuess game = new RealisticGuess(); game.Start(); } }
} </lang>
Clojure
<lang Clojure>(require '[clojure.string :as str])
(defn guess-game [low high]
(printf "Think of a number between %s and %s.\n (use (h)igh (l)ow (c)orrect)\n" low high) (loop [guess (/ (inc (- high low)) 2) [step & more] (next (iterate #(/ % 2) guess))] (printf "I guess %s\n=> " (Math/round (float guess))) (flush) (case (first (str/lower-case (read))) \h (recur (- guess step) more) \l (recur (+ guess step) more) \c (println "Huzzah!") (do (println "Invalid input.") (recur guess step)))))</lang>
Output
user=> (guess-game 1 100) Think of a number between 1 and 100. (use (h)igh (l)ow (c)orrect) I guess 50 => l I guess 63 => h I guess 56 => l I guess 59 => l I guess 61 => c Huzzah!
D
<lang d>import std.stdio, std.string;
void main() {
immutable mnOrig = 1, mxOrig = 10; int mn = mnOrig, mx = mxOrig;
writefln( "Think of a number between %d and %d and wait for me to guess it. On every guess of mine you should state whether the guess was too high, too low, or equal to your number by typing h, l, or =", mn, mx);
LOOP: for (int i = 1; ; i++) { immutable guess = (mn + mx) / 2; writef("Guess %2d is: %2d. The score for which is (h,l,=): ", i, guess); immutable string txt = readln().strip().toLower();
switch (txt) { case "h": mx = guess - 1; break; case "l": mn = guess + 1; break; case "=": writeln(" Yeehaw!!"); break LOOP; default: writefln(" I don't understand your input '%s'.", txt); continue LOOP; }
if (mn > mx || mn < mnOrig || mx > mxOrig) { writeln("Please check your scoring as" ~ " I cannot find the value"); break; } } writeln("\nThanks for keeping score.");
}</lang>
- Output:
Think of a number between 1 and 10 and wait for me to guess it. On every guess of mine you should state whether the guess was too high, too low, or equal to your number by typing h, l, or = Guess 1 is: 5. The score for which is (h,l,=): l Guess 2 is: 8. The score for which is (h,l,=): h Guess 3 is: 6. The score for which is (h,l,=): l Guess 4 is: 7. The score for which is (h,l,=): = Yeehaw!! Thanks for keeping score.
Erlang
<lang erlang>% Implemented by Arjun Sunel -module(guess_game). -export([main/0]).
main() -> L = 1 , % Lower Limit U = 100, % Upper Limit
io:fwrite("Player 1 : Guess my number between ~p and ", [L]), io:fwrite("and ~p until you get it right.\n", [U]), N = random:uniform(100), guess(L,U,N).
guess(L,U,N) -> K = (L+U) div 2, io:format("Player 2 : Number guessed : ~p~n",[K]), if K=:=N -> io:format("Well guessed!! by Player 2\n"); true -> if K > N -> io:format("Player 1 : Your guess is too high!\n"), guess(L,K,N); true -> io:format("Player 1 : Your guess is too low!\n"), guess(K,U,N) end end.</lang>
- Output:
Player 1 : Guess my number between 1 and and 100 until you get it right. Player 2 : Number guessed : 50 Player 1 : Your guess is too high! Player 2 : Number guessed : 25 Player 1 : Your guess is too high! Player 2 : Number guessed : 13 Player 1 : Your guess is too high! Player 2 : Number guessed : 7 Player 1 : Your guess is too low! Player 2 : Number guessed : 10 Well guessed!! by Player 2 ok
Euphoria
<lang euphoria>include get.e include wildcard.e
sequence Respons integer min, max, Guess min = 0 max = 100
printf(1,"Think of a number between %d and %d.\n",{min,max}) puts(1,"On every guess of mine you should state whether my guess was\n") puts(1,"too high, too low, or equal to your number by typing 'h', 'l', or '='\n")
while 1 do
if max < min then puts(1,"I think something is strange here...\n") exit end if Guess = floor((max-min)/2+min) printf(1,"My guess is %d, is this correct? ", Guess) Respons = upper(prompt_string("")) if Respons[1] = 'H' then max = Guess-1 elsif Respons[1] = 'L' then min = Guess+1 elsif Respons[1] = '=' then puts(1,"I did it!\n") exit else puts(1,"I do not understand that...\n") end if
end while</lang>
Fantom
<lang fantom> class Main {
public static Void main () { Int lowerLimit := 1 Int higherLimit := 100
echo ("Think of a number between 1 and 100") echo ("Press 'enter' when ready") Env.cur.in.readLine while (true) { if (higherLimit < lowerLimit) { // check that player is not cheating! echo ("Something has gone wrong ... I give up") break } myGuess := (higherLimit + lowerLimit) / 2 echo ("My guess is $myGuess") echo ("Enter 'H' if your number is higher, 'L' if lower, or 'E' if equal") switch (Env.cur.in.readLine.trim.upper) { case "E": echo ("I got it correct - thankyou!") break // game over case "H": lowerLimit = myGuess + 1 case "L": higherLimit = myGuess - 1 default: echo ("Pardon? Let's try that again") } } }
} </lang>
Example:
Think of a number between 1 and 100 Press 'enter' when ready My guess is 50 Enter 'H' if your number is higher, 'L' if lower, or 'E' if equal a Pardon? Let's try that again My guess is 50 Enter 'H' if your number is higher, 'L' if lower, or 'E' if equal l My guess is 25 Enter 'H' if your number is higher, 'L' if lower, or 'E' if equal h My guess is 37 Enter 'H' if your number is higher, 'L' if lower, or 'E' if equal h My guess is 43 Enter 'H' if your number is higher, 'L' if lower, or 'E' if equal h My guess is 46 Enter 'H' if your number is higher, 'L' if lower, or 'E' if equal h My guess is 48 Enter 'H' if your number is higher, 'L' if lower, or 'E' if equal l My guess is 47 Enter 'H' if your number is higher, 'L' if lower, or 'E' if equal e I got it correct - thankyou!
Fortran
<lang fortran>program Guess_a_number_Player
implicit none integer, parameter :: limit = 100 integer :: guess, mx = limit, mn = 1 real :: rnum character(1) :: score write(*, "(a, i0, a)") "Think of a number between 1 and ", limit, & " and I will try to guess it." write(*, "(a)") "You score my guess by entering: h if my guess is higher than that number" write(*, "(a)") " l if my guess is lower than that number" write(*, "(a/)") " c if my guess is the same as that number"
call random_seed call random_number(rnum) guess = rnum * limit + 1 do write(*, "(a, i0, a,)", advance='no') "My quess is: ", guess, " Score(h, l or c)?: " read*, score select case(score) case("l", "L") mn = guess guess = (mx-guess+1) / 2 + mn case("h", "H") mx = guess guess = mx - (guess-mn+1) / 2
case("c", "C") write(*, "(a)") "I solved it!" exit
case default write(*, "(a)") "I did not understand that" end select end do
end program</lang> Output
Think of a number between 1 and 100 and I will try to guess it. You score my guess by entering: h if my guess is higher than that number l if my guess is lower than that number c if my guess is the same as that number My guess is: 58 Score(h, l or c)?: h My guess is: 29 Score(h, l or c)?: l My guess is: 44 Score(h, l or c)?: l My guess is: 51 Score(h, l or c)?: l My guess is: 55 Score(h, l or c)?: l My guess is: 57 Score(h, l or c)?: c I solved it!
Go
Go's binary search function (sort.Search()
) is general enough to be able to do this type of task, as mentioned in the documentation for the function itself.[1]
<lang go>package main
import (
"fmt" "sort"
)
func main() {
lower, upper := 0, 100 fmt.Printf(`Instructions:
Think of integer number from %d (inclusive) to %d (exclusive) and I will guess it. After each guess, I will ask you if it is less than or equal to some number, and you will respond with "yes" or "no". `, lower, upper)
answer := sort.Search(upper-lower, func (i int) bool { fmt.Printf("Is your number less than or equal to %d? ", lower+i) s := "" fmt.Scanf("%s", &s) return s != "" && s[0] == 'y' }) fmt.Printf("Your number is %d.\n", lower+answer)
}</lang>
Manual solution: <lang go>package main
import (
"bufio" "fmt" "os"
)
func main() {
lower, upper := 1, 100 fmt.Printf(`Instructions:
Think of integer number from %d (inclusive) to %d (inclusive) and I will guess it. After each guess, you respond with l,h,or c depending on if my guess was too low, too high, or correct. Press enter when you are thinking of a number. `, lower, upper)
in := bufio.NewReader(os.Stdin) in.ReadString('\n') for { guess := (upper+lower)/2 fmt.Printf("My guess: %d (l/h/c) ", guess) s, err := in.ReadString('\n') if err != nil { fmt.Println("\nSo, bye.") return } switch s { case "l\n": lower = guess + 1 case "h\n": upper = guess - 1 case "c\n": fmt.Println("I did it. :)") return default: fmt.Println("Please respond by pressing l, h, or c") } }
}</lang>
Icon and Unicon
<lang Icon> procedure main ()
lower_limit := 1 higher_limit := 100 write ("Think of a number between 1 and 100") write ("Press 'enter' when ready") read ()
repeat { if (higher_limit < lower_limit) then { # check that player is not cheating! write ("Something has gone wrong ... I give up") exit () } my_guess := (higher_limit + lower_limit) / 2 write ("My guess is ", my_guess) write ("Enter 'H' if your number is higher, 'L' if lower, or 'E' if equal") reply := map(trim(read ())) case (reply) of { "e" : { write ("I got it correct - thankyou!") exit () # game over } "h" : lower_limit := my_guess + 1 "l" : higher_limit := my_guess - 1 default : write ("Pardon? Let's try that again") } }
end </lang>
J
<lang j>require 'misc' guess=:3 :0
'lo hi'=.y while.lo < hi do. smoutput 'guessing a number between ',(":lo),' and ',":hi guess=.lo+?hi-lo select.{.deb tolower prompt 'is it ',(":guess),'? ' case.'y'do. smoutput 'Win!' return. case.'l'do. lo=.guess+1 case.'h'do. hi=.guess-1 case.'q'do. smoutput 'giving up' return. case. do. smouput 'options: yes, low, high, quit' end. end.
)</lang>
Example session:
<lang> guess 1 100 guessing a number between 1 and 100 is it 86? hi guessing a number between 1 and 85 is it 56? hi guessing a number between 1 and 55 is it 24? lo guessing a number between 25 and 55 is it 29? lo guessing a number between 30 and 55 is it 43? lo guessing a number between 44 and 55 is it 53? hi guessing a number between 44 and 52 is it 51? hi guessing a number between 44 and 50 is it 48? lo guessing a number between 49 and 50 is it 49? lo 50</lang>
This could be made more efficient by replacing guess=.lo+?hi-lo
with guess=.<.-:lo+hi
. (The above example would have finished on the first guess, but the range 1..100 would never take more than 6 guesses -- the remaining answers would be determined after six guesses.)
Java
A clever solution that uses the built-in binary search functions with a virtual list.
<lang java5>import java.util.AbstractList; import java.util.Collections; import java.util.Scanner;
public class GuessNumber {
public static final int LOWER = 0, UPPER = 100; public static void main(String[] args) {
System.out.printf("Instructions:\n" + "Think of integer number from %d (inclusive) to %d (exclusive) and\n" + "I will guess it. After each guess, you respond with L, H, or C depending\n" + "on if my guess was too low, too high, or correct.\n", LOWER, UPPER); int result = Collections.binarySearch(new AbstractList<Integer>() { private final Scanner in = new Scanner(System.in); public int size() { return UPPER - LOWER; } public Integer get(int i) { System.out.printf("My guess is: %d. Is it too high, too low, or correct? (H/L/C) ", LOWER+i); String s = in.nextLine(); assert s.length() > 0; switch (Character.toLowerCase(s.charAt(0))) { case 'l': return -1; case 'h': return 1; case 'c': return 0; } return -1; } }, 0); if (result < 0) System.out.println("That is impossible."); else System.out.printf("Your number is %d.\n", result);
}
}</lang>
JavaScript
Spidermonkey version
A boring solution that does nothing clever or inscrutable.
Well, it does use recursion for the guessing function, but that's OK because the depth is bounded by LOG2 of the range. That's not true if the user changes his number, but then he gets what he deserves.
<lang javascript>#!/usr/bin/env js
var DONE = RIGHT = 0, HIGH = 1, LOW = -1;
function main() {
showInstructions(); while (guess(1, 100) !== DONE);
}
function guess(low, high) {
if (low > high) { print("I can't guess it. Perhaps you changed your number."); return DONE; } var g = Math.floor((low + high) / 2); var result = getResult(g); switch (result) { case RIGHT: return DONE; case LOW: return guess(g + 1, high); case HIGH: return guess(low, g - 1); }
}
function getResult(g) {
while(true) { putstr('Is it ' + g + '? '); var ans = readline().toUpperCase().replace(/^\s+/, ) + ' '; switch (ans[0]) { case 'R': print('I got it! Thanks for the game.'); return RIGHT; case 'L': return LOW; case 'H': return HIGH; default: print('Please tell me if I am "high", "low" or "right".'); } }
}
function showInstructions() {
print('Think of a number between 1 and 100 and I will try to guess it.'); print('After I guess, type "low", "high" or "right", and then press enter.'); putstr("When you've thought of a number press enter."); readline();
}
main(); </lang>
An example session:
Think of a number between 1 and 100 and I will try to guess it. After I guess, type "low", "high" or "right", and then press enter. When you've thought of a number press enter. Is it 50? high Is it 25? high Is it 12? low Is it 18? high Is it 15? high Is it 13? right I got it! Thanks for the game.
Another example session:
Think of a number between 1 and 100 and I will try to guess it. After I guess, type "low", "high" or "right", and then press enter. When you've thought of a number press enter. Is it 50? n Please tell me if I am "high", "low" or "right". Is it 50? h Is it 25? h Is it 12? h Is it 6? h Is it 3? h Is it 1? h I can't guess it. Perhaps you changed your number.
Lasso
<lang Lasso>#!/usr/bin/lasso9
local( mini=0, maxi=100, status = false, count = 0, response, guess )
stdoutnl('Think of a number between ' + #mini + ' and ' + #maxi + ' Each time I guess indicate if I was to high (H), to low (L) or just right (R).')
while(not #status) => {
if(not(#mini <= #maxi)) => {
stdout('I think you are trying to cheat me. I will not play anymore.') #status = true
else
#guess = ((#maxi - #mini) /2 ) + #mini
stdout('You are thinking on ' + #guess + ' ') #response = null
// the following bits wait until the terminal gives you back a line of input while(not #response or #response -> size == 0) => { #response = file_stdin -> readSomeBytes(1024, 1000) } #response -> replace(bytes('\n'), bytes())
match(string(#response)) => { case('L') #mini = #guess + 1 #count++ case('H') #maxi = #guess - 1 #count++ case('R') stdout('Am I smart or smart! I guessed it in ' + #count ' tries!') #status = true case() stdout('Are you having issues reading instructions? ') } } }</lang>
Examples:
Think of a number between 0 and 100 Each time I guess indicate if I was to high (H), to low (L) or just right (R). You are thinking on 50 l You are thinking on 75 l You are thinking on 88 h You are thinking on 81 r Am I smart or smart! I guessed it in 4 tries!
Think of a number between 0 and 100 Each time I guess indicate if I was to high (H), to low (L) or just right (R). You are thinking on 50 k Are you having issues reading instructions? You are thinking on 50 tr Are you having issues reading instructions? You are thinking on 50 l You are thinking on 75 l You are thinking on 88 l You are thinking on 94 l You are thinking on 97 l You are thinking on 99 h You are thinking on 98 r Am I smart or smart! I guessed it in 6 tries!
You are thinking on 50 h You are thinking on 24 h You are thinking on 11 l You are thinking on 17 l You are thinking on 20 l You are thinking on 22 l You are thinking on 23 l I think you are trying to cheat me. I will not play anymore.
Liberty BASIC
<lang lb>mini=0 maxi=100
print "Think of a number between ";mini;" and ";maxi print "Each time I guess a number you must state whether my" print "guess was too high, too low, or equal to your number." print
while response$<>"="
if not(mini<=maxi) then
print "Error" exit while end if guess=int((maxi-mini)/2)+mini print "My guess is ";guess;". Type L for low, H for high, = for correct." input response$ response$=upper$(response$) select case response$ case "L" mini=guess+1 case "H"
maxi=guess-1
case "=" print guess;" is correct." exit while case else print "Your response was not helpful." end select
wend
print "Thanks for playing." </lang>
Lua
<lang>function wait(waittime)--wait function is used so that app will not quit immediately
local timer = os.time() repeat until os.time() == timer + waittime
end
upperBound = 100
lowerBound = 0
print("Think of an integer between 1 to 100.")
print("I will try to guess it.")
while true do
upper1 = upperBound+1
upper2 = upperBound-1
if upperBound == lowerBound or upper1 == lowerBound or upper2 == lowerBound or lowerBound > upperBound then--make sure player is not cheating
io.write("You're cheating! I'm not playing anymore. Goodbye.")
wait(3)
break
else
Guess = math.floor((upperBound + lowerBound)/2)--guessing mechanism
print("My guess is: "..Guess..". Is it too high, too low, or correct? (h/l/c)")
input = io.read()
if input == "h" then --higher upperBound = Guess elseif input == "l" then --lower lowerBound = Guess elseif input == "c" then --correct io.write("So I win? Thanks for playing with me.") wait(3) break else print("Invalid input. Please try again. ") end end end </lang>
Mathematica
<lang>guessnumber[min0_, max0_] :=
DynamicModule[{min = min0, max = max0, guess, correct = False}, guess[] := Round@Mean@{min, max}; Dynamic@If[correct, Row@{"Your number is ", guess[], "."}, Column@{Row@{"I guess ", guess[], "."}, Row@{Button["too high", max = guess[]], Button["too low", min = guess[]], Button["correct", correct = True]}}]];
guessnumber[1, 100]</lang>
Modula-2
<lang modula2>MODULE raden;
IMPORT InOut;
VAR done, ok : BOOLEAN;
guess, upp, low : CARDINAL; res : CHAR;
BEGIN
InOut.WriteString ("Choose a number between 0 and 1000."); InOut.WriteLn; InOut.WriteLn; upp := 1000; low := 0; REPEAT ok := FALSE; guess := ( ( upp - low ) DIV 2 ) + low; InOut.WriteString ("My guess is"); InOut.WriteCard (guess, 4); InOut.Write (11C); InOut.WriteString ("How did I score? 'L' = too low, 'H' = too high, 'Q' = OK : "); InOut.WriteBf; REPEAT InOut.Read (res); res := CAP (res) UNTIL (res = 'Q') OR (res = 'L') OR (res = 'H'); CASE res OF 'L' : low := guess | 'H' : upp := guess ELSE ok := TRUE END; UNTIL ok; InOut.WriteString ("So the number is"); InOut.WriteCard (guess, 4); InOut.WriteLn; InOut.WriteString ("Thanks for letting me play with you."); InOut.WriteLn
END raden.</lang>Example:
raden Choose a number between 0 and 1000. My guess is 500 How did I score? 'L' = too low, 'H' = too high, 'Q' = OK : l My guess is 750 How did I score? 'L' = too low, 'H' = too high, 'Q' = OK : h My guess is 625 How did I score? 'L' = too low, 'H' = too high, 'Q' = OK : h My guess is 562 How did I score? 'L' = too low, 'H' = too high, 'Q' = OK : l My guess is 593 How did I score? 'L' = too low, 'H' = too high, 'Q' = OK : l My guess is 609 How did I score? 'L' = too low, 'H' = too high, 'Q' = OK : h My guess is 601 How did I score? 'L' = too low, 'H' = too high, 'Q' = OK : h My guess is 597 How did I score? 'L' = too low, 'H' = too high, 'Q' = OK : l My guess is 599 How did I score? 'L' = too low, 'H' = too high, 'Q' = OK : l My guess is 600 How did I score? 'L' = too low, 'H' = too high, 'Q' = OK : q So the number is 600 Thanks for letting me play with you.
Objective-C
A clever solution that uses the built-in binary search functions with a virtual list.
<lang objc>#import <Foundation/Foundation.h>
@interface GuessNumberFakeArray : NSArray {
int lower, upper;
} - (instancetype)initWithLower:(int)l andUpper:(int)u; @end
@implementation GuessNumberFakeArray - (instancetype)initWithLower:(int)l andUpper:(int)u {
if ((self = [super init])) { lower = l; upper = u; } return self;
} - (NSUInteger)count { return upper-lower; } - (id)objectAtIndex:(NSUInteger)i {
printf("My guess is: %d. Is it too high, too low, or correct? (H/L/C) ", lower + (int)i); char input[2] = " "; scanf("%1s", input); switch (tolower(input[0])) { case 'l': return @-1; case 'h': return @1; case 'c': return @0; } return nil;
} @end
- define LOWER 0
- define UPPER 100
int main(int argc, const char *argv[]) {
@autoreleasepool { printf("Instructions:\n" "Think of integer number from %d (inclusive) to %d (exclusive) and\n" "I will guess it. After each guess, you respond with L, H, or C depending\n" "on if my guess was too low, too high, or correct.\n", LOWER, UPPER); NSUInteger result = [[[GuessNumberFakeArray alloc] initWithLower:LOWER andUpper:UPPER] indexOfObject:[NSNumber numberWithInt: 0] inSortedRange:NSMakeRange(0, UPPER - LOWER) options:0 usingComparator:^(id x, id y){ return [x compare: y]; }]; if (result == NSNotFound) printf("That is impossible.\n"); else printf("Your number is %d.", LOWER + (int)result); } return 0;
}</lang>
PARI/GP
<lang parigp> guessnumber2(b)={ my(c=0,d=b,a=0); for(x=1,b,
for(y=1,b, if(a<c||a==c||a==d||a>d, a=random(b), break() ) ); print("I guess "a" am I h,l,or e ?"); g=input(); if(g==h, d=a, if(g==l, c=a, if(g==e, break() ) ) ) );
} </lang>
Pascal
<lang pascal>Program GuessIt(input, output);
var
done, ok: boolean; guess, upp, low: integer; res: char;
begin
writeln ('Choose a number between 0 and 1000.'); write ('Press Enter and I will start to guess the number.'); readln; upp := 1000; low := 0; repeat ok := false; guess := ( ( upp - low ) div 2 ) + low; write ('My guess is: ', guess:4); write ('. How did i score? l = too low, h = too high, c = correct : '); repeat readln (res); res := lowercase(res); until (res = 'c') or (res = 'l') or (res = 'h'); case res of 'l': low := guess; 'h': upp := guess; else ok := true end; until ok; writeln ('So the number is: ', guess:4); writeln ('It was nice to play with you.');
end.</lang> Output:
:> ./GuessTheNumberPlayerFeedback Choose a number between 0 and 1000. Press Enter and I will start to guess the number. My guess is: 500. How did i score? 'l' = too low, 'h' = too high, 'c' = correct : h My guess is: 250. How did i score? 'l' = too low, 'h' = too high, 'c' = correct : h My guess is: 125. How did i score? 'l' = too low, 'h' = too high, 'c' = correct : l My guess is: 187. How did i score? 'l' = too low, 'h' = too high, 'c' = correct : h My guess is: 156. How did i score? 'l' = too low, 'h' = too high, 'c' = correct : h My guess is: 140. How did i score? 'l' = too low, 'h' = too high, 'c' = correct : h My guess is: 132. How did i score? 'l' = too low, 'h' = too high, 'c' = correct : l My guess is: 136. How did i score? 'l' = too low, 'h' = too high, 'c' = correct : l My guess is: 138. How did i score? 'l' = too low, 'h' = too high, 'c' = correct : h My guess is: 137. How did i score? 'l' = too low, 'h' = too high, 'c' = correct : c So the number is: 137 It was nice to play with you.
Perl
<lang perl>#!/usr/bin/perl
my $min = 1; my $max = 99; my $guess = int(rand $max) + $min; my $tries = 0;
print "=>> Think of a number between $min and $max and I'll guess it!\n Press <ENTER> when are you ready... ";
<STDIN>;
{
do {
$tries++; print "\n=>> My guess is: $guess Is your number higher, lower, or equal? (h/l/e)\n> ";
my $score = <STDIN>;
if ($max <= $min) { print "\nI give up...\n" and last; } elsif ($score =~ /^h/i) { $min = $guess + 1; } elsif ($score =~ /^l/i) { $max = $guess; } elsif ($score =~ /^e/i) { print "\nI knew it! It took me only $tries tries.\n" and last; } else { print "error: invalid score\n"; }
$guess = int(($max + $min) / 2);
} while(1);
}</lang>
=>> Think of a number between 1 and 99 and I'll guess it! Press <ENTER> when are you ready... =>> My guess is: 88. Is your number higher, lower or equal? (h/l/e) > l =>> My guess is: 44. Is your number higher, lower or equal? (h/l/e) > l =>> My guess is: 22. Is your number higher, lower or equal? (h/l/e) > h =>> My guess is: 33. Is your number higher, lower or equal? (h/l/e) > l =>> My guess is: 28. Is your number higher, lower or equal? (h/l/e) > e I knew it! It took me only 5 tries.
Perl 6
<lang perl6>multi sub MAIN() { MAIN(0, 100) } multi sub MAIN($min is copy where ($min >= 0), $max is copy where ($max > $min)) {
say "Think of a number between $min and $max and I'll guess it!"; while $min <= $max { my $guess = (($max + $min)/2).floor; given lc prompt "My guess is $guess. Is your number higher, lower or equal? " { when /^e/ { say "I knew it!"; exit } when /^h/ { $min = $guess + 1 } when /^l/ { $max = $guess } default { say "WHAT!?!?!" } } } say "How can your number be both higher and lower than $max?!?!?";
}</lang>
You may execute this program with 'perl6 program' or with 'perl6 program min max'. Perl 6 creates a usage for us if we don't give the right parameters. It also parses the parameters for us and provides them via $min and $max. We use multi-subs to provide two MAIN subroutines so the user is able to choose between min and max parameters and no parameters at all, in which case min is set to 0 and max to 100.
PicoLisp
<lang PicoLisp>(de guessTheNumber (Min Max)
(prinl "Think of a number between " Min " and " Max ".") (prinl "On every guess of mine you should state whether my guess was") (prinl "too high, too low, or equal to your number by typing 'h', 'l', Or '='") (use Guess (loop (NIL (> Max Min) (prinl "I think somthing is strange here...") ) (prin "My guess is " (setq Guess (+ Min (/ (- Max Min) 2))) ",is this correct? " ) (flush) (NIL (case (uppc (car (line))) ("H" (setq Max Guess)) ("L" (setq Min Guess)) ("=" (nil (prinl "I did it!"))) (T (prinl "I do not understand that...")) ) ) ) ) )</lang>
Output:
: (guessTheNumber 1 99) Think of a number between 1 and 99. On every guess of mine you should state whether my guess was too high, too low, or equal to your number by typing 'h', 'l', Or '=' My guess is 50,is this correct? h My guess is 25,is this correct? h My guess is 13,is this correct? l My guess is 19,is this correct? l My guess is 22,is this correct? = I did it!
PureBasic
<lang PureBasic>min=0 max=100
If OpenConsole()
PrintN("Think of a number between "+Str(min)+" and "+Str(max)+".") PrintN("On every guess of mine you should state whether my guess was") PrintN("too high, too low, or equal to your number by typing 'h', 'l', Or '='") Repeat If max<=min PrintN("I think somthing is strange here...") Break EndIf Guess=(max-min)/2+min Print("My guess is "+Str(Guess)+",is this correct? "): Respons.s=UCase(Input()) If Respons="H": max=Guess-1 ElseIf Respons="L": min=Guess+1 ElseIf Respons="=" PrintN("I did it!") Break Else PrintN("I do not understand that...") EndIf ForEver
EndIf</lang>
Python
<lang python>inclusive_range = mn, mx = (1, 10)
print(\ Think of a number between %i and %i and wait for me to guess it. On every guess of mine you should state whether the guess was too high, too low, or equal to your number by typing h, l, or = % inclusive_range)
i = 0 while True:
i += 1 guess = (mn+mx)//2 txt = input("Guess %2i is: %2i. The score for which is (h,l,=): " % (i, guess)).strip().lower()[0] if txt not in 'hl=': print(" I don't understand your input of '%s' ?" % txt) continue if txt == 'h': mx = guess-1 if txt == 'l': mn = guess+1 if txt == '=': print(" Ye-Haw!!") break if (mn > mx) or (mn < inclusive_range[0]) or (mx > inclusive_range[1]): print("Please check your scoring as I cannot find the value") break
print("\nThanks for keeping score.")</lang>
Sample Game-play
Think of a number between 1 and 10 and wait for me to guess it. On every guess of mine you should state whether the guess was too high, too low, or equal to your number by typing h, l, or = Guess 1 is: 5. The score for which is (h,l,=): l Guess 2 is: 8. The score for which is (h,l,=): l Guess 3 is: 9. The score for which is (h,l,=): l Guess 4 is: 10. The score for which is (h,l,=): = Ye-Haw!! Thanks for keeping score.
Obscure solution using bisect module
Hacky solution using a fake list class and the bisect
module from the standard library to do the binary search.
<lang python>import bisect try: input = raw_input except: pass
class GuessNumberFakeList(object):
def __getitem__(self, i): s = input("Is your number less than or equal to %d?" % i) return 0 if s.lower().startswith('y') else -1
LOWER, UPPER = 0, 100
if __name__ == "__main__":
print("""Instructions:
Think of integer number from %d (inclusive) to %d (exclusive) and I will guess it. After each guess, I will ask you if it is less than or equal to some number, and you will respond with "yes" or "no". """ % (LOWER, UPPER))
result = bisect.bisect_left(GuessNumberFakeList(), 0, LOWER, UPPER) print("Your number is %d." % result)</lang>
- Sample output
Instructions: Think of integer number from 0 (inclusive) to 100 (exclusive) and I will guess it. After each guess, I will ask you if it is less than or equal to some number, and you will respond with "yes" or "no". Is your number less than or equal to 50?no Is your number less than or equal to 75?yes Is your number less than or equal to 63?no Is your number less than or equal to 69?no Is your number less than or equal to 72?yes Is your number less than or equal to 71?no Your number is 72.
Racket
<lang Racket>#lang racket
(define (guess low high)
(define (input-loop available) (define input (car (string->list (symbol->string (read))))) (if (member input available) input (begin (printf "Invalid Input\n") (input-loop available)))) (define (guess-loop low high) (define guess (floor (/ (+ low high) 2))) (printf "My guess is ~a.\n" guess) (define input (input-loop (list #\c #\l #\h))) (case input ((#\c) (displayln "I knew it!\n")) ((#\l) (guess-loop low (sub1 guess))) ((#\h) (guess-loop (add1 guess) high)))) (printf "Think of a number between ~a and ~a.
Use (h)igh, (l)ow and (c)orrect to guide me.\n" low high)
(guess-loop low high))</lang>
Another way with loops and mutation <lang Racket>#lang racket (define (guess minimum maximum)
(printf "Think of a number from ~a to ~a, use (h)igh, (l)ow and (c)orrect." minimum maximum) (define input "") (do ((guess (round (/ (+ maximum minimum) 2)) (round (/ (+ maximum minimum) 2)))) ((string=? input "c")) (printf "My guess is: ~a\n(h/l/=) > ") (when (string=? input "h") (begin (display "OK...") (set! maximum (sub1 guess)))) (when (string=? input "l") (begin (display "OK...") (set! minimum (add1 guess))))) (displayln "I was RIGHT!"))</lang>
REXX
with positive integers
This version only handles positive integers. <lang rexx>/*REXX pgm to play guess-the-number (with itself) with positive integers*/ parse arg low high . if low== then low=1 if high== then high=1000 ?=random(low,high) say try="Try to guess my integer (it's between" low 'and' high" inclusive)."
do j=1 say try; say call guesser select when guess>? then info=right("It's too high.",40) when guess<? then info=right("It's too low. ",40) otherwise leave end /*select*/ end /*j*/
say say 'Congratulations! You guessed the secret number in' j "tries." exit /*stick a fork in it, we're done.*/ /*──────────────────────────────────GUESSER subroutine──────────────────*/ guesser: oguess=guess if pos('high',info)\==0 then high=guess if pos('low' ,info)\==0 then low =guess guess=low+(high-low)%2 if guess=oguess then guess=guess+1 say 'My guess is' guess return</lang> output shown is from playing several games:
Try to guess my number (it's between 1 and 1000 inclusive). My guess is 500 It's too low. My guess is 750 It's too low. My guess is 875 It's too high. My guess is 812 It's too low. My guess is 843 It's too high. My guess is 827 It's too high. My guess is 819 It's too low. My guess is 823 It's too low. My guess is 825 Congratulations! You guessed the secret number in 9 tries. _________________________________________________________________ Try to guess my number (it's between 1 and 1000 inclusive). My guess is 500 It's too high. My guess is 250 It's too high. My guess is 125 It's too high. My guess is 63 It's too high. My guess is 32 It's too low. My guess is 47 It's too low. My guess is 55 It's too low. My guess is 59 It's too high. My guess is 57 It's too low. My guess is 58 Congratulations! You guessed the secret number in 10 tries. _________________________________________________________________ Try to guess my number (it's between 1 and 1000 inclusive). My guess is 500 It's too high. My guess is 250 It's too low. My guess is 375 It's too high. My guess is 312 It's too low. My guess is 343 It's too low. My guess is 359 It's too high. My guess is 351 Congratulations! You guessed the secret number in 7 tries. _________________________________________________________________ Try to guess my number (it's between 1 and 1000 inclusive). My guess is 500 It's too low. My guess is 750 It's too high. My guess is 625 It's too low. My guess is 687 It's too high. My guess is 656 Congratulations! You guessed the secret number in 5 tries. _________________________________________________________________ Try to guess my number (it's between 1 and 1000 inclusive). My guess is 500 It's too high. My guess is 250 It's too high. My guess is 125 Congratulations! You guessed the secret number in 3 tries.
with positive numbers
This version handles decimal fractions (method used only generates numbers with a one-digit decimal fraction, but this
REXX program will handle any length of decimal fractions than can be generated with the current numeric digits.
<lang rexx>/*REXX pgm to play guess-the-number (with itself) with positive numbers.*/
parse arg low high .
if low== then low=1
if high== then high=1000
?=random(low*10,high*10)/10 /*make it tough, it may be a fraction.*/
say
try="Try to guess my number (it's between" low 'and' high" inclusive)."
do j=1; say try; say call guesser select when guess>? then info=right("It's too high.",40) when guess<? then info=right("It's too low. ",40) otherwise leave end /*select*/ end /*j*/
say
say 'Congratulations! You guessed the secret number in' j "tries."
exit /*stick a fork in it, we're done.*/
/*──────────────────────────────────GUESSER subroutine──────────────────*/
guesser: oguess=guess
if pos('high',info)\==0 then high=guess
if pos('low' ,info)\==0 then low =guess
guess=(low+(high-low)/2) / 1
if guess=oguess then guess=guess+1
say 'My guess is' guess
return</lang>
output will be about ten times longer (that is, has ten more times the guesses).
Ruby
Computer plays versus itself <lang ruby>def play(low, high, turns=1)
num = (low + high) / 2 print "guessing #{num}\t" case is_it?(num) when 1 puts "too high" play(low, num - 1, turns + 1) when -1 puts "too low" play(num + 1, high, turns + 1) else puts "found the number in #{turns} turns." end
end
def is_it?(num)
num <=> $number
end
low, high = 1, 100 $number = rand(low .. high)
puts "guess a number between #{low} and #{high}" play(low, high)</lang>
Example
guess a number between 1 and 100 guessing 50 too high guessing 25 too low guessing 37 too high guessing 31 too high guessing 28 too low guessing 29 too low guessing 30 found the number in 7 turns.
Rust
<lang rust>use std::io::stdio::stdin; use std::str;
fn main() {
let mut low = 1; let mut high = 100; let mut current_guess = calculate_guess(low, high); let mut number_of_guesses = 1; let mut stdin = stdin(); println!("Hello, please choose a number between {} and {} and remember it.", low, high); println("Got it? Good. Now I shall guess it using only the power of my mind.\n"); loop { println!("My guess is {:d}. Is that too [h]igh, too [l]ow or is it [e]qual to it? ", current_guess); println("(please type h, l or e and then hit enter)"); let buf: &mut [u8] = [0u8, ..8]; let num_bytes = stdin.read(buf); let answer = str::from_utf8(buf).slice_to(num_bytes.unwrap()).trim(); match answer { "e" | "E" => { println!("Jolly good! I got it in only {} tries!", number_of_guesses); break; } "l" | "L" => { low = current_guess; current_guess = calculate_guess(low, high); number_of_guesses += 1; } "h" | "H" => { high = current_guess; current_guess = calculate_guess(low, high); number_of_guesses += 1; } _ => println("sorry, I didn't quite get that")
} if low == high { println!("Your number must be {}. Or maybe you forgot it? It happens!", low); break; } if low > high { println("Uh, I think something went wrong. Entirely my fault, I'm sure!"); break; } }
}
fn calculate_guess(low: int, high: int) -> int {
(low + high) / 2
}
</lang>
Scheme
<lang scheme>(define minimum 1) (define maximum 100)
(display "Enter a number from ")(display minimum) (display " to ")(display maximum)(display ": ") (define number (read))
(define input "")
(do ((guess (round (/ (+ maximum minimum) 2)) (round (/ (+ maximum minimum) 2))))
((string= input "=")) (display "Is it ")(display guess)(display "?\n(h/l/=) > ") (set! input (symbol->string (read))) (if (string= input "h") (begin (display "OK...") (set! maximum (- guess 1)))) (if (string= input "l") (begin (display "OK...") (set! minimum (+ guess 1)))))
(display "I was RIGHT!\n")</lang>
Seed7
The program reads the possible commands (l, h, c, q) as single keypresses from the KEYBOARD with getc. It is also possible to quit the program with q. The program recognices also a situation when there is only one possible number left and the command is not c.
<lang seed7>$ include "seed7_05.s7i"; $ include "keybd.s7i";
const proc: main is func
local var boolean: okay is FALSE; var boolean: quit is FALSE; var integer: low is 1; var integer: high is 1000; var integer: guess is 0; var char: command is ' '; begin writeln("Choose a number between 1 and 1000."); write("Press Enter and I will start to guess the number."); readln; repeat guess := low + (high - low) div 2; write("My guess is: " <& guess); write(". How did I score (l=too low, h=too high, c=correct, q=quit)? "); flush(OUT); repeat command := lower(getc(KEYBOARD)); until command in {'l', 'h', 'c', 'q'}; writeln(command); case command of when {'l'}: low := succ(guess); when {'h'}: high := pred(guess); when {'c'}: okay := TRUE; when {'q'}: quit := TRUE; end case; until quit or okay or low > high; if not quit then writeln("So the number is: " <& guess); if low > high then writeln("Why did you cheat?"); end if; end if; writeln("It was nice to play with you."); end func;</lang>
Example
Choose a number between 1 and 1000. Press Enter and I will start to guess the number. My guess is: 500. How did I score (l=too low, h=too high, c=correct, q=quit)? h My guess is: 250. How did I score (l=too low, h=too high, c=correct, q=quit)? l My guess is: 375. How did I score (l=too low, h=too high, c=correct, q=quit)? h My guess is: 312. How did I score (l=too low, h=too high, c=correct, q=quit)? l My guess is: 343. How did I score (l=too low, h=too high, c=correct, q=quit)? l My guess is: 359. How did I score (l=too low, h=too high, c=correct, q=quit)? l My guess is: 367. How did I score (l=too low, h=too high, c=correct, q=quit)? h My guess is: 363. How did I score (l=too low, h=too high, c=correct, q=quit)? l My guess is: 365. How did I score (l=too low, h=too high, c=correct, q=quit)? c So the number is: 365 It was nice to play with you.
Smalltalk
Create a class like this:
<lang smalltalk>Object subclass: #NumberGuesser
instanceVariableNames: classVariableNames: poolDictionaries: category: 'Rosettacode'
</lang>
Enter these methods into it:
<lang smalltalk>playBetween: low and: high
Transcript clear. number := (low to: high) atRandom. self playBetween: low and: high atTurn: 1.
playBetween: low and: high atTurn: turn
| guess | guess := (low + ((high - low) / 2)) asInteger. self showGuessing: guess atTurn: turn. true caseOf: { [number > guess] -> [self showNumberBeing: #low. self playBetween: guess and: high atTurn: turn+1 ]. [number < guess] -> [self showNumberBeing: #high. self playBetween: low and: guess atTurn: turn+1 ]. [true] -> [self showNumberFoundAtTurnNr: turn ] }.
showGuessing: guess atTurn: turn
Transcript show: ('{1}. guessing: {2}' format: {turn asString. guess asString}).
showNumberBeing: comparisonToken
Transcript show: ' ==> too ', (comparisonToken asString); cr.
showNumberFoundAtTurnNr: turn
Transcript show: (' ==> found the number in {1} turn(s).' format: {turn asString}); cr.
</lang>
If you'd rather not use caseOf:
you can write playBetween:and:atTurn:
like this:
<lang smalltalk> playBetween: low and: high atTurn: turn
| guess | guess := (low + ((high - low) / 2)) asInteger. self showGuessing: guess atTurn: turn. (guess = number) ifTrue: [self showNumberFoundAtTurnNr: turn ] ifFalse: [ (number > guess) ifTrue: [self showNumberBeing: #low. self playBetween: guess and: high atTurn: turn+1 ] ifFalse: [self showNumberBeing: #high. self playBetween: low and: guess atTurn: turn+1]].
</lang>
And evaluate this in a Workspace:
<lang smalltalk>g := NumberGuesser new. g playBetween: 1 and: 100. </lang>
Sample output:
1. guessing: 50 ==> too low 2. guessing: 75 ==> too low 3. guessing: 87 ==> too high 4. guessing: 81 ==> too low 5. guessing: 84 ==> too low 6. guessing: 85 ==> found the number in 6 turn(s).
Standard ML
A clever solution that uses the built-in binary search functions with a virtual list.
<lang sml>structure GuessNumberHelper : MONO_ARRAY = struct
type elem = order type array = int * int fun length (lo, hi) = hi - lo fun sub ((lo, hi), i) = let val n = lo + i in print ("My guess is: " ^ Int.toString (lo+i) ^ ". Is it too high, too low, or correct? (H/L/C) "); let val str = valOf (TextIO.inputLine TextIO.stdIn) in case Char.toLower (String.sub (str, 0)) of #"l" => GREATER | #"h" => LESS | #"c" => EQUAL end end
(* dummy implementations for not-needed functions *) type vector = unit val maxLen = Array.maxLen fun update _ = raise Domain fun array _ = raise Domain fun fromList _ = raise Domain fun tabulate _ = raise Domain fun vector _ = raise Domain fun copy _ = raise Domain fun copyVec _ = raise Domain fun appi _ = raise Domain fun app _ = raise Domain fun modifyi _ = raise Domain fun modify _ = raise Domain fun foldli _ = raise Domain fun foldl _ = raise Domain fun foldri _ = raise Domain fun foldr _ = raise Domain fun findi _ = raise Domain fun find _ = raise Domain fun exists _ = raise Domain fun all _ = raise Domain fun collate _ = raise Domain
end
structure GuessNumberBSearch = BSearchFn (GuessNumberHelper)
val lower = 0 val upper = 100;
print ("Instructions:\n" ^
"Think of integer number from " ^ Int.toString lower ^ " (inclusive) to " ^ Int.toString upper ^ " (exclusive) and\n" ^ "I will guess it. After each guess, you respond with L, H, or C depending\n" ^ "on if my guess was too low, too high, or correct.\n");
case GuessNumberBSearch.bsearch (fn (_, x) => x) ((), (lower, upper)) of
NONE => print "That is impossible.\n"
| SOME (result, _) => print ("Your number is " ^ Int.toString result ^ ".\n")</lang>
Tcl
<lang tcl>set from 1 set to 10 fconfigure stdout -buffering none while 1 {
set guess [expr {($from+$to) / 2}] puts -nonewline "Guess: $guess\tWas it lower (<) equal (=) or higher (>)? " switch -- [gets stdin] {
< { set from [expr {$guess + 1}] } > { set to [expr {$guess - 1}] } = { puts "Found it: $guess" break } default { puts "What sort of a response was that?!" }
} if {$to < $from} {
puts "No answer possible?!" break
}
}</lang> Sample run:
Guess: 5 Was it lower (<) equal (=) or higher (>)? < Guess: 8 Was it lower (<) equal (=) or higher (>)? > Guess: 6 Was it lower (<) equal (=) or higher (>)? = Found it: 6
VBA
<lang vba> Sub GuessNumberPlayer() Dim iGuess As Integer, iLow As Integer, iHigh As Integer, iCount As Integer Dim vSolved As Variant On Error GoTo ErrHandler MsgBox "Pick a number between 1 and 100. I will guess it!", vbInformation + vbOKOnly, "Rosetta Code | Guess the Number Player" iCount = 0 iLow = 1 iHigh = 100 Do While Not vSolved = "Y"
iGuess = Application.WorksheetFunction.RandBetween(iLow, iHigh) iCount = iCount + 1
CheckGuess:
vSolved = InputBox("My guess: " & iGuess & vbCr & vbCr & "Y = Yes, correct guess" & vbCr & _ "H = your number is higher" & vbCr & "L = your number is lower" & vbCr & "X = exit game", "Rosetta Code | Guess the Number Player | Guess " & iCount) Select Case vSolved Case "Y", "y": GoTo CorrectGuess Case "X", "x": Exit Sub Case "H", "h": iLow = iGuess + 1 Case "L", "l": iHigh = iGuess - 1 Case Else: GoTo CheckGuess End Select
Loop CorrectGuess:
MsgBox "I guessed number " & iGuess & " in just " & iCount & " attempts!", vbExclamation + vbOKOnly, "Rosetta Code | Guess the Number Player" Exit Sub
ErrHandler:
MsgBox "Not possible. Were you cheating?!", vbCritical + vbOKOnly, "Rosetta Code | Guess the Number Player | ERROR!"
End Sub </lang>
XPL0
<lang XPL0>include c:\cxpl\codes; \intrinsic 'code' declarations int Hi, Lo, Guess; [Text(0, "Think of a number between 1 and 100 then press a key."); if ChIn(1) then []; Lo:= 1; Hi:= 101; loop [Guess:= (Lo+Hi)/2;
Text(0, "^M^JIs it "); IntOut(0, Guess); Text(0, " (Y = yes, H = too high, L = too low)? "); case ChIn(1) of ^L,^l: Lo:= Guess; ^H,^h: Hi:= Guess; ^Y,^y: quit other ChOut(0, 7\bel\); ];
Text(0, "^M^JYippee!"); ]</lang>
Example output:
Think of a number between 1 and 100 then press a key. Is it 51 (Y = yes, H = too high, L = too low)? H Is it 26 (Y = yes, H = too high, L = too low)? H Is it 13 (Y = yes, H = too high, L = too low)? L Is it 19 (Y = yes, H = too high, L = too low)? H Is it 16 (Y = yes, H = too high, L = too low)? L Is it 17 (Y = yes, H = too high, L = too low)? Y Yippee!