function side(arr) {
arr[0] = arr[2];
}
function func1(a, b, c = 3) {
c = 10;
side(arguments);
console.log(a + b + c);
}
function func2(a, b, c) {
c = 10;
side(arguments);
console.log(a + b + c);
}
func1(1, 1, 1);
func2(1, 1, 1);
12 12
21 21
12 21
21 12