Rust猜数字之循环

     extern crate rand;

     use std::io;
     use std::cmp::Ordering;
     use rand::Rng;

     fn main() {
         println!("Guess the number!");

         let secret_number = rand::thread_rng().gen_range(1, 101);

         println!("The secret number is: {}", secret_number);

         loop {
             println!("Please input your guess.");

             let mut guess = String::new();

             io::stdin().read_line(&mut guess)
                 .ok()
                 .expect("failed to read line");

             let guess: u32 = guess.trim().parse()
                 .ok()
                 .expect("Please type a number!");

             println!("You guessed: {}", guess);

             match guess.cmp(&secret_number) {
                 Ordering::Less    => println!("Too small!"),
                 Ordering::Greater => println!("Too big!"),
                 Ordering::Equal   => println!("You win!"),
             }
         }
     }

     $ cargo run
        Compiling guessing_game v0.0.1 (file:///home/you/projects/guessing_game)
          Running `target/guessing_game`
     Guess the number!
     The secret number is: 59
     Please input your guess.
     45
     You guessed: 45
     Too small!
     Please input your guess.
     60
     You guessed: 60
     Too big!
     Please input your guess.
     59
     You guessed: 59
     You win!
     Please input your guess.
     quit
     thread '<main>' panicked at 'Please type a number!'

     extern crate rand;

     use std::io;
     use std::cmp::Ordering;
     use rand::Rng;

     fn main() {
         println!("Guess the number!");

         let secret_number = rand::thread_rng().gen_range(1, 101);

         println!("The secret number is: {}", secret_number);

         loop {
             println!("Please input your guess.");

             let mut guess = String::new();

             io::stdin().read_line(&mut guess)
                 .ok()
                 .expect("failed to read line");

             let guess: u32 = guess.trim().parse()
                 .ok()
                 .expect("Please type a number!");

             println!("You guessed: {}", guess);

             match guess.cmp(&secret_number) {
                 Ordering::Less    => println!("Too small!"),
                 Ordering::Greater => println!("Too big!"),
                 Ordering::Equal   => {
                     println!("You win!");
                     break;
                 }
             }
         }
     }

     extern crate rand;

     use std::io;
     use std::cmp::Ordering;
     use rand::Rng;

     fn main() {
         println!("Guess the number!");

         let secret_number = rand::thread_rng().gen_range(1, 101);

         println!("The secret number is: {}", secret_number);

         loop {
             println!("Please input your guess.");

             let mut guess = String::new();

             io::stdin().read_line(&mut guess)
                 .ok()
                 .expect("failed to read line");

             let guess: u32 = match guess.trim().parse() {
                 Ok(num) => num,
                 Err(_) => continue,
             };

             println!("You guessed: {}", guess);

             match guess.cmp(&secret_number) {
                 Ordering::Less    => println!("Too small!"),
                 Ordering::Greater => println!("Too big!"),
                 Ordering::Equal   => {
                     println!("You win!");
                     break;
                 }
             }
         }
     }

     let guess: u32 = match guess.trim().parse() {
           Ok(num) => num,
           Err(_) => continue,
     };

     $ cargo run
        Compiling guessing_game v0.0.1 (file:///home/you/projects/guessing_game)
          Running `target/guessing_game`
     Guess the number!
     The secret number is: 61
     Please input your guess.
     10
     You guessed: 10
     Too small!
     Please input your guess.
     99
     You guessed: 99
     Too big!
     Please input your guess.
     foo
     Please input your guess.
     61
     You guessed: 61
     You win!

     extern crate rand;

     use std::io;
     use std::cmp::Ordering;
     use rand::Rng;

     fn main() {
         println!("Guess the number!");

         let secret_number = rand::thread_rng().gen_range(1, 101);

         loop {
             println!("Please input your guess.");

             let mut guess = String::new();

             io::stdin().read_line(&mut guess)
                 .ok()
                 .expect("failed to read line");

             let guess: u32 = match guess.trim().parse() {
                 Ok(num) => num,
                 Err(_) => continue,
             };

             println!("You guessed: {}", guess);

             match guess.cmp(&secret_number) {
                 Ordering::Less    => println!("Too small!"),
                 Ordering::Greater => println!("Too big!"),
                 Ordering::Equal   => {
                     println!("You win!");
                     break;
                 }
             }
         }
     }