Menu

Menu
You are encouraged to solve this task according to the task description, using any language you may know.

Given a list containing a number of strings of which one is to be selected and a prompt string, create a function that:

• Print a textual menu formatted as an index value followed by its corresponding string for each item in the list.
• Prompt the user to enter a number.
• Return the string corresponding to the index number.

The function should reject input that is not an integer or is an out of range integer index by recreating the whole menu before asking again for a number. The function should return an empty string if called with an empty list.

For test purposes use the four phrases: “fee fie”, “huff and puff”, “mirror mirror” and “tick tock” in a list.

Note: This task is fashioned after the action of the Bash select statement.

AutoHotkey

<lang autohotkey>GoSub, CreateGUI return

Submit: Gui, Submit, NoHide If Input =

GuiControl,,Output

Else If Input not between 1 and 4 {

Gui, Destroy
Sleep, 500
GoSub, CreateGUI

} Else {

GuiControlGet, string,,Text%Input%
GuiControl,,Output,% SubStr(string,4)

} return

CreateGUI: list = fee fie,huff and puff,mirror mirror,tick tock Loop, Parse, list, `,

Gui, Add, Text, vText%A_Index%, %A_Index%: %A_LoopField%

Gui, Add, Text, ym, Which is from the three pigs? Gui, Add, Edit, vInput gSubmit Gui, Add, Edit, vOutput Gui, Show return

GuiClose: ExitApp</lang>

BASIC

Works with: QuickBasic version 4.5

<lang qbasic> function sel$(choices$(), prompt$)

  if ubound(choices$) - lbound(choices$) = 0 then sel$ = ""
  ret$ = ""
  do
     for i = lbound(choices$) to ubound(choices$)
        print i; ": "; choices$(i)
     next i
     input ;prompt$, index
     if index <= ubound(choices$) and index >= lbound(choices$) then ret$ = choices$(index)
  while ret$ = ""
  sel$ = ret$

end function</lang>

C

<lang c>#include <stdio.h>

1. include <stdlib.h>
2. include <string.h>

const char *menu_select(const char **items, const char *prompt) {

 int i, nchoices;
 int choice;

 if (items==NULL) return NULL;
 while(1) {
   for(i=0; items[i] != NULL; i++) {
     printf("%d) %s\n", i+1, items[i]);
   }
   nchoices = i;
   if ( prompt != NULL )
     printf("%s ", prompt);
   else
     printf("Choice? ");
   scanf("%d", &choice);
   if ( (choice > 0) && (choice <= nchoices) ) break;
   printf("Choose from 1 to %d\n\n", nchoices);
 }
 return items[choice-1];

}</lang>

<lang c>const char *menu[] = {

 "fee fie", "huff and puff", "mirror mirror", "tick tock", NULL

};

int main() {

 printf("You chose: %s\n", menu_select(menu, "Which is from the three pigs?"));
 return EXIT_SUCCESS;

}</lang>

C++

This example is incorrect. Please fix the code and remove this message. Details: The dataEntry function should return a string, not void.

<lang cpp>#include <iostream>

1. include <boost/regex.hpp>
2. include <cstdlib>
3. include <string>

using namespace std;

void printMenu(const string *, int); //prints menu bool checkEntry(string, const string *, int); //checks whether entered data is in required range void dataEntry(const string *, int); //function that performs it all

void dataEntry(const string *terms, int size) {

  if (size == 0) { //we return an empty string when we call the function with an empty list
     cout << '\n';
     return;
  }
  printMenu(terms, size);
  cout << "Enter a number from 1 to " << size << " :\n";

  string entry;
  cin >> entry;

  bool ok = checkEntry(entry, terms, size);
  while (!ok) {
     printMenu(terms, size);
     cout << "Enter a number from 1 to " << size << " :\n";
     cin >> entry;
     ok = checkEntry(entry, terms, size);
  }

  int number = atoi(entry.c_str());
  cout << terms[number - 1] << '\n' ;

}

void printMenu(const string *terms, int num) {

  for (int i = 1 ; i < num + 1 ; i++) {
     cout << i << ')' << terms[ i - 1 ] << '\n';
  }

}

bool checkEntry(string myEntry, const string *terms, int num) {

  boost::regex e("^\\d+$");
  if (!boost::regex_match(myEntry, e)) 
     return false;
  int number = atoi(myEntry.c_str());
  if (number < 1 || number > num) 
     return false;
  return true;

}

int main( ) {

  const string terms[ ] = { "fee fie" , "huff and puff" , "mirror mirror" , "tick tock" };
  int size = sizeof terms / sizeof *terms;
  dataEntry(terms, size);
  return 0;

}</lang>

Clojure

<lang clojure>(defn menu [prompt choices]

 (if (empty? choices) 
   ""
   (let [menutxt (apply str (interleave
                             (iterate inc 1)
                             (map #(str \space % \newline) choices)))]
     (println menutxt)
     (print prompt)
     (flush)
     (let [index (read-string (read-line))]
       ; verify
       (if (or (not (integer? index))
               (> index (count choices))
               (< index 1))
         ; try again
         (recur prompt choices)
         ; ok
         (nth choices (dec index)))))))

(println "You chose: "

        (menu "Which is from the three pigs: "
              ["fee fie" "huff and puff" "mirror mirror" "tick tock"]))</lang>

Common Lisp

<lang lisp>(defun select (prompt choices)

 (if (null choices)
   ""
   (do (n)
       ((and n (<= 0 n (1- (length choices))))
        (nth n choices))
     (format t "~&~a~%" prompt)
     (loop for n from 0
           for c in choices
           do (format t "  ~d) ~a~%" n c))
     (force-output)
     (setf n (parse-integer (read-line *standard-input* nil)
                            :junk-allowed t)))))</lang>

D

<lang d>import std.stdio; import std.conv; import std.string; void main() {

       char[][]items = ["fee fie","huff and puff","mirror mirror","tick tock"];
       writefln("You chose %s",doSelect(items));

}

char[]doSelect(char[][]input) {

       if (!input.length) return "";
       char[]line;
       int choice;
       do {
               writefln("Choose one:");
               foreach(i,item;input) {
                       writefln("%d) %s",i,item);
               }
               writef("> ");
               line = readln();
               line = chomp(line);
               choice = ValidChoice(input.length-1,line);
       } while (choice == -1);
       // we have a valid choice
       return input[choice];

}

int ValidChoice(int max,char[]input) {

       int tmp;
       try tmp = toInt(input);
       catch(Error e) return -1;
       if (tmp <= max && tmp >= 0) {
               return tmp;
       }
       return -1;

}</lang>

Factor

<lang factor>USE: formatting

print-menu ( seq -- )

   [ 1 + swap "%d - %s\n" printf ] each-index
   "Your choice? " write flush ;

select ( seq -- result )

   dup print-menu
   readln string>number [
       1 - swap 2dup bounds-check?
       [ nth ] [ nip select ] if
   ] [ select ] if* ;</lang>

Example usage:

( scratchpad ) { "fee fie" "huff and puff" "mirror mirror" "tick tock" } select
1 - fee fie
2 - huff and puff
3 - mirror mirror
4 - tick tock
Your choice? 1

--- Data stack:
"fee fie"

Haskell

<lang Haskell>module RosettaSelect where

import Data.Maybe (listToMaybe) import Control.Monad (guard)

select :: [String] -> IO String select [] = return "" select menu = do

 putStr $ showMenu menu
 putStr "Choose an item: "
 choice <- getLine
 maybe (select menu) return $ choose menu choice

showMenu :: [String] -> String showMenu menu = unlines [show n ++ ") " ++ item | (n, item) <- zip [1..] menu]

choose :: [String] -> String -> Maybe String choose menu choice = do

 n <- maybeRead choice
 guard $ n > 0
 listToMaybe $ drop (n-1) menu

maybeRead :: Read a => String -> Maybe a maybeRead = fmap fst . listToMaybe . filter (null . snd) . reads</lang>

Example usage, at the GHCI prompt: <lang Haskell>*RosettaSelect> select ["fee fie", "huff and puff", "mirror mirror", "tick tock"] 1) fee fie 2) huff and puff 3) mirror mirror 4) tick tock Choose an item: 3 "mirror mirror"

• RosettaSelect></lang>

J

Solution: <lang j>require'misc' showMenu =: i.@# smoutput@,&":&> ' '&,&.> makeMsg =: 'Choose a number 0..' , ': ',~ ":@<:@# errorMsg =: [ smoutput bind 'Please choose a valid number!'

select=: ({::~ _&".@prompt@(makeMsg [ showMenu)) :: ($:@errorMsg)</lang> See Talk page for explanation of code.

Example use: <lang j> select 'fee fie'; 'huff and puff'; 'mirror mirror'; 'tick tock'</lang>

This would display:

0 fee fie
1 huff and puff
2 mirror mirror
3 tick tock
choose a number 0..3:

And, if the user responded with 2, would return: mirror mirror

Java

<lang java5>public static String select(List<String> list, String prompt){

   if(list.size() == 0) return "";
   Scanner sc = new Scanner(System.in);
   String ret = null;
   do{
       for(int i=0;i<list.size();i++){
           System.out.println(i + ": "+list.get(i));
       }
       System.out.print(prompt);
       int index = sc.nextInt();
       if(index >= 0 && index < list.size()){
           ret = list.get(index);
       }
   }while(ret == null);
   return ret;

}</lang>

JavaScript

Works with: JScript

for the I/O.

<lang javascript>function select(question, choices) {

   var prompt = "";
   for (var i in choices) 
       prompt += i + ". " + choices[i] + "\n";
   prompt += question;

   var input;
   while (1) {
       WScript.Echo(prompt);
       input = parseInt( WScript.StdIn.readLine() );
       if (0 <= input && input < choices.length)
           break;
       WScript.Echo("\nTry again.");
   }
   return input;

}

var choices = ['fee fie', 'huff and puff', 'mirror mirror', 'tick tock']; var choice = select("Which is from the three pigs?", choices); WScript.Echo("you selected: " + choice + " -> " + choices[choice]);</lang>

Logo

Works with: UCB Logo

<lang logo>to select :prompt [:options]

 foreach :options [(print # ?)]
 forever [
   type :prompt type "| |
   make "n readword
   if (and [number? :n] [:n >= 1] [:n <= count :options]) [output item :n :options]
   print sentence [Must enter a number between 1 and] count :options
 ]

end

print equal? [huff and puff] (select

 [Which is from the three pigs?]
 [fee fie] [huff and puff] [mirror mirror] [tick tock])

</lang>

Lua

<lang lua>function choice(choices)

 for i, v in ipairs(choices) do print(i, v) end

 print"Enter your choice"
 local selection = io.read() + 0

 if choices[selection] then print(choices[selection])
 else choice(choices)
 end

end

choice{"fee fie", "huff and puff", "mirror mirror", "tick tock"}</lang>

OCaml

<lang ocaml>let rec select choices prompt = (* "choices" is an array of strings *)

 if Array.length choices = 0 then invalid_arg "no choices";
 Array.iteri (Printf.printf "%d: %s\n") choices;
 print_string prompt;
 let index = read_int () in
   if index >= 0 && index < Array.length choices then
     choices.(index)
   else
     select choices prompt</lang>

Oz

<lang oz>declare

 fun {Select Prompt Items}
    case Items of nil then ""
    else

for Item in Items Index in 1..{Length Items} do {System.showInfo Index#") "#Item} end {System.printInfo Prompt} try {Nth Items {ReadInt}} catch _ then {Select Prompt Items} end

    end
 end

 fun {ReadInt}
    class TextFile from Open.file Open.text end
    StdIo = {New TextFile init(name:stdin)}
 in
    {String.toInt {StdIo getS($)}}
 end
 
 Item = {Select "Which is from the three pigs: "

["fee fie" "huff and puff" "mirror mirror" "tick tock"]}

in

 {System.showInfo "You chose: "#Item}</lang>

Perl

<lang perl>sub menu {

       my ($prompt,@array) = @_;
       return  unless @array;

       print "  $_: $array[$_]\n" for(0..$#array);
       print $prompt;
       $n = <>;
       return $array[$n] if $n =~ /^\d+$/ and defined $array[$n];
       return &menu($prompt,@array);

}

@a = ('fee fie', 'huff and puff', 'mirror mirror', 'tick tock'); $prompt = 'Which is from the three pigs: ';

$a = &menu($prompt,@a);

print "You chose: $a\n";</lang>

Python

<lang python>def _menu(items):

   for indexitem in enumerate(items):
       print ("  %2i) %s" % indexitem)

def _ok(reply, itemcount):

   try:
       n = int(reply)
       return 0 <= n < itemcount
   except:
       return False
   

def selector(items, prompt):

   'Prompt to select an item from the items'
   if not items: return 
   reply = -1
   itemcount = len(items)
   while not _ok(reply, itemcount):
       _menu(items)
       # Use input instead of raw_input for Python 3.x
       reply = raw_input(prompt).strip()
   return items[int(reply)]

if __name__ == '__main__':

   items = ['fee fie', 'huff and puff', 'mirror mirror', 'tick tock']
   item = selector(items, 'Which is from the three pigs: ')
   print ("You chose: " + item)</lang>

Sample runs:

   0) fee fie
   1) huff and puff
   2) mirror mirror
   3) tick tock
Which is from the three pigs:  -1
   0) fee fie
   1) huff and puff
   2) mirror mirror
   3) tick tock
Which is from the three pigs:      0
You chose: fee fie
>>> ================================ RESTART ================================
>>> 
   0) fee fie
   1) huff and puff
   2) mirror mirror
   3) tick tock
Which is from the three pigs: 4
   0) fee fie
   1) huff and puff
   2) mirror mirror
   3) tick tock
Which is from the three pigs: 3
You chose: tick tock

R

Uses menu. <lang R>showmenu <- function() {

  choices <- c("fee fie", "huff and puff", "mirror mirror", "tick tock")
  ans <- menu(choices)
  if(ans==0) "" else choices[ans]

} str <- showmenu()</lang>

REBOL

<lang REBOL>REBOL [ Title: "Text Menu" Author: oofoe Date: 2009-12-08 URL: http://rosettacode.org/wiki/Select ]

choices: ["fee fie" "huff and puff" "mirror mirror" "tick tock"] choice: ""

valid?: func [ choices [block! list! series!] choice ][ if error? try [choice: to-integer choice] [return false] all [0 < choice choice <= length? choices] ]

while [not valid? choices choice][ repeat i length? choices [print [" " i ":" choices/:i]] choice: ask "Which is from the three pigs? " ] print ["You chose:" pick choices to-integer choice]</lang>

Output:

   1 : fee fie
   2 : huff and puff
   3 : mirror mirror
   4 : tick tock
Which is from the three pigs? klf
   1 : fee fie
   2 : huff and puff
   3 : mirror mirror
   4 : tick tock
Which is from the three pigs? 5
   1 : fee fie
   2 : huff and puff
   3 : mirror mirror
   4 : tick tock
Which is from the three pigs? 2
You chose: huff and puff

Ruby

<lang ruby>def select(prompt, items)

 return "" if items.length == 0
 while true
   items.each_index {|i| puts "#{i}. #{items[i]}"}
   print "#{prompt}: "
   begin
     answer = Integer(gets())
   rescue ArgumentError
     redo
   end
   return items[answer] if answer.between?(0, items.length - 1)
 end

end

1. test empty list

response = select("Which is empty", []) puts "empty list returns: >#{response}<" puts ""

1. "real" test

items = ['fee fie', 'huff and puff', 'mirror mirror', 'tick tock'] response = select("Which is from the three pigs", items) puts "you chose: >#{response}<"</lang>

Tcl

<lang tcl>proc select {prompt choices} {

   set nc [llength $choices]
   if {!$nc} {

return ""

   }
   set numWidth [string length $nc]
   while true {

set i 0 foreach s $choices { puts [format "  %-*d: %s" $numWidth [incr i] $s] } puts -nonewline "$prompt: " flush stdout gets stdin num if {[string is int -strict $num] && $num >= 1 && $num <= $nc} { incr num -1 return [lindex $choices $num] }

   }

}</lang> Testing it out interactively... <lang tcl>% puts >[select test {}]< >< % puts >[select "Which is from the three pigs" {

   "fee fie" "huff and puff" "mirror mirror" "tick tock"

}]<

 1: fee fie
 2: huff and puff
 3: mirror mirror
 4: tick tock

Which is from the three pigs: 0

 1: fee fie
 2: huff and puff
 3: mirror mirror
 4: tick tock

Which is from the three pigs: skdfjhgz

 1: fee fie
 2: huff and puff
 3: mirror mirror
 4: tick tock

Which is from the three pigs:

 1: fee fie
 2: huff and puff
 3: mirror mirror
 4: tick tock

Which is from the three pigs: 5

 1: fee fie
 2: huff and puff
 3: mirror mirror
 4: tick tock

Which is from the three pigs: 2 >huff and puff<</lang>

UNIX Shell

The bash shell with its [select] statement. <lang bash>bash$ PS3='Which is from the three pigs: ' bash$ select phrase in 'fee fie' 'huff and puff' 'mirror mirror' 'tick tock'; do > if -n $phrase ; then > PHRASE=$phrase > echo PHRASE is $PHRASE > break > else > echo 'invalid.' > fi > done 1) fee fie 2) huff and puff 3) mirror mirror 4) tick tock Which is from the three pigs: 5 invalid. Which is from the three pigs: 2 PHRASE is huff and puff bash$</lang>