#include <iostream>

using namespace std;

int square(int* a) {
    return *a *= *a;
}

void Swap(int* x, int* y) {
    int temp = *x;
    *x = *y;
    *y = temp;
}

void Div(int* a) {
    *a /= 2;
}

int main() {
    int a = 10;

    int b = 20;

    Swap(&a, &b);

    cout << a << endl;
    cout << b << endl;

    int c = 30;
    Div(&c);
    cout << c << endl;
}