fn test_pointer_arithmetic() {
    arr := [1, 2, 3, 4]
    unsafe {
        mut parr := &int(arr.data)
        assert 1 == *parr
        parr++
        assert 2 == *parr
        parr++
        assert 3 == *parr
        parr_add_one := *(parr + 1)
        assert parr_add_one == 4
        assert *(parr + 1) == 4
    }
}

struct User {
mut:
    name string
}

fn modify_ptr(mut user User) {
    user.name = 'Bob'
}

fn test_mut_ptr() {
    mut user := &User{'Peter'}
    assert user.name == 'Peter'
    modify_ptr(mut user)
    assert user.name == 'Bob'
    println(user)
}

/*
fn test_multi_level_pointer_dereferencing() {
    n := 100
    pn := &n
    ppn := &pn
    unsafe {
        mut pppn := &ppn
        ***pppn = 300
        pppa := ***int(pppn)
        assert 300 == ***pppa
    }
    assert n == 300    // updated by the unsafe pointer manipulation
}
*/