struct Point {
    x: int;
    y: int;
}

fn add_points(p1: Point, p2: Point = Point { x: 10, y: 10 }) -> Point {
    return Point {
        x: p1.x + p2.x,
        y: p1.y + p2.y
    };
}

fn operation(a: int, b: int = 5 * 2) -> int {
    return a + b;
}

fn main() {
    var p1 = Point { x: 5, y: 5 };
    var res1 = add_points(p1);
    
    println "res1.x: {res1.x}, res1.y: {res1.y}";
    assert(res1.x == 15, "result is not 15");
    assert(res1.y == 15, "result is not 15");

    var p2 = Point { x: 1, y: 1 };
    var p3 = Point { x: 5, y: 5 };
    var res2 = add_points(p3, p2);
    
    println "res2.x: {res2.x}, res2.y: {res2.y}";
    assert(res2.x == 6, "result is not 6");
    assert(res2.y == 6, "result is not 6");
    
    println "operation(10): {operation(10)}";
    assert(operation(10) == 20, "result is not 20");
    
    println "operation(10, 5): {operation(10, 5)}";
    assert(operation(10, 5) == 15, "result is not 15");
}