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Bulls and cows: Difference between revisions
→{{header|Ruby}}
Line 3,373:
puts "Bulls: #{bulls}; Cows: #{cows}"
end</lang>
=={{header|Rust}}==
{{works with|Rust|0.9}}
<lang rust>use std::iter::range_inclusive;
use std::rand::{task_rng, Rng};
use std::io;
use std::str;
use std::option::collect;
use std::io::stdio::StdReader;
use std::str::from_char;
use std::iter::FromIterator;
use std::hashmap::HashSet;
static NUMBER_OF_DIGITS: uint = 4;
static LOWEST_DIGIT: uint = 1;
static HIGHEST_DIGIT: uint = 9;
fn generate_digits() -> ~[uint] {
task_rng().sample(range_inclusive(LOWEST_DIGIT, HIGHEST_DIGIT), NUMBER_OF_DIGITS)
}
fn read_input(reader: &mut StdReader) -> ~str {
let mut buf = [0u8, ..32];
let num_bytes = reader.read(buf).unwrap();
return str::from_utf8(buf).slice_to(num_bytes).trim().to_owned();
}
fn parse_guess_string(guess: &str) -> Option<~[uint]> {
let digit_chars = guess.chars();
let digit_options = digit_chars.map(|c| from_str::<uint>(from_char(c)));
// std::option::collect is a cool little function that goes through an iterator
// and returns a None if it hits a None. If not it will return a Some that
// contains a vector containing the unwrapped values of the iterator
let digits_maybe: Option<~[uint]> = collect(digit_options);
match digits_maybe {
Some(ref digits) => {
if digits.len() != NUMBER_OF_DIGITS {
println!("you need to guess with {:u} digits", NUMBER_OF_DIGITS);
return None;
}
if digits.iter().any(|&digit| digit < LOWEST_DIGIT || digit > HIGHEST_DIGIT) {
println("digit out of range");
return None;
}
let digits_set: HashSet<&uint> = FromIterator::from_iterator(&mut digits.iter());
if digits_set.len() != NUMBER_OF_DIGITS {
println("no duplicates!");
return None;
}
},
None => println("non-numeric input, please try again")
}
return digits_maybe;
}
fn calculate_score(digits: &[uint], guess: &[uint]) -> (uint, uint) {
let mut bulls = 0;
let mut cows = 0;
for i in range(0, digits.len()) {
let mut j = guess.iter();
let pos_maybe: Option<uint> = j.position(|&a| -> bool {a == digits[i]});
match pos_maybe {
None => (),
Some(pos) if pos == i => bulls += 1,
Some(_) => cows += 1
}
}
return (bulls, cows);
}
fn main() {
let mut reader = io::stdin();
loop {
let digits = generate_digits();
println!("I have chosen my {} digits. Please guess what they are", NUMBER_OF_DIGITS);
loop {
let guess_string = read_input(&mut reader);
let digits_maybe = parse_guess_string(guess_string);
match digits_maybe {
None => continue,
Some(guess_digits) => {
let (bulls, cows) = calculate_score(digits, guess_digits);
if bulls == NUMBER_OF_DIGITS {
println("you win!");
break;
} else {
println!("bulls: {:u}, cows: {:u}", bulls, cows);
}
}
}
}
}
}</lang>
=={{header|Scala}}==
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