fn main(){
    let vec = vec![1i32,2i32,3i32,4i32];
    let x = vec.len();
    println!("{:?}",usize::max_value());
    println!("{:?}",u64::max_value());

    println!("{:?}",isize::max_value());
    println!("{:?}",i64::max_value());
}