rust变量与可变性
fn main() {
//let x = 5;
let mut x = 5;
//通过const定义常量名称要大写,并且值不可更改
const Y:i32=6;
println!("Y is {}",Y);
println!("The value of x is {}", x);
x = 6;
println!("The value of x is {}", x);
//如果要覆盖上一个变量 需要使用let
//如果不是let而改变了x的类型会出错
//x = 1.23;
let x = "hello";
println!("x type changed to string ,{}",x);
let x = x.len();
println!("x len is {}",x)
}