How to Swap Two Numbers in a Function Using Functions from Other C++ Files?

In this lab for my C++ class, the goal is to finish defining the function in the Main.cpp file called Swap(). I know how to swap to values normally because all it takes is to make one of the values equal to a temp value and then begin swapping the values of the variables from there.

But from what this lab is telling me, I need to use some of the other functions that are defined in the Number.cpp file in order to accomplish my goal.

I have been stumped on this one for a long while, so any help would be greatly appreciated.

Below is my code:

Main.cpp (Finish defining the Swap() function)

#include "Number.h"
#include <iostream>
using namespace std;

void Swap(Number& num1, Number& num2) {   // num1 and num2 are passed by reference
    /* Type your code here */
}

int main() {
    Number num1 = Number(19);
    Number num2 = Number(178);

    Swap(num1, num2);
    cout << "num1 = " << num1.GetNum() << ", num2 = " << num2.GetNum() << endl;

    return 0;
}

Number.cpp (READ ONLY)

#include "Number.h"

Number::Number(int number) {
    num = number;
}

void Number::SetNum(int number) {
    num = number;
}

int Number::GetNum() {
    return num;
}

Number.h (READ ONLY)

#ifndef NUMBERH
#define NUMBERH

class Number {
    public:
        Number(int number);
        void SetNum(int number);
        int GetNum();

    private:
        int num;
};

#endif