Statement-Arguments

Passing argument by value

By default the arguments are passed by value, but attention, as we have already seen in the previous chapter, the operator = behaves differently depending on the type:

fn myfunc(arg1: u32, arg2: Vec<u32>){
    println!("{}", arg1);
    println!("{:?}", arg2);
}

fn main(){
    let mut a = 10;
    let mut b: Vec<u32> = Vec::from([1, 2, 3]);
    myfunc(a, b);

    println!("{}", a);
    println!("{:?}", b);
}

Passing argument by reference.

fn myfunc(arg1: &mut u32, arg2: &mut Vec<u32>){
    *arg1 += 10;
    arg2[1] += 10;
    println!("{}", *arg1);
    println!("{:?}", *arg2);
}

fn main(){
    let mut a = 10;
    let mut b: Vec<u32> = Vec::from([1, 2, 3]);
    myfunc(&mut a, &mut b);
    a += 1;
    b[0] += 1;
    println!("{}", a);
    println!("{:?}", b);
}