Answer 1

#include <iostream>
using namespace std;

void swap(int &a, int &b)
{
a += b;
b = a - b;
a -= b;
}

int main()
{
int a, b;
cout << "Enter two numbers: ";
cin >> a >> b;
cout << "A = " << a << "\nB = " << b;
swap(a, b);
cout << "\nSwapped!\n" << "A = " << a << "\nB = " << b;
}

No need for pointers, can just pass by reference.