注意区别语句和表达式哟。

Rust是一门基于表示式的语言，牢记！！！

fn main() {
   println!("Hello world!");
   another_function(5, 6);

    let y = {
	let x = 3;
	x + 1
    };
    println!("The value of y is: {}", y);
  
    let x = plus_one(5);
    println!("The value of x is: {}", x);
    
}

fn another_function(x: i32, y: i32) {
    println!("The value of x is: {}", x);
    println!("The value of y is: {}", y);
}

fn plus_one(x: i32) -> i32 {
    x + 1
}