C++ :: Sorting 3 Numbers By Ascending Orders?

We've only covered up to Functions and how to use reference variables inside the function parameter.

One of the hw problem that was assigned was to write a void function that takes three parameters( num1, num2, num3) by reference and sorts their values into ascending order, so that num1 has the lowest, num2 the middle value, and num3 the highest value. For example, if user enters: 14, -4, 8, then the output should look like this:

-4
8
14

I've completed the program with a bunch of if/ else if statements but I was wondering if there was a more efficient way to sort the numbers. Bear in mind, we've only covered materials up to functions so I can't use any other new techniques that we haven't cover yet. Here is my code:

// This program will take three int parameters by reference and sorts their value into ascending order
//so that num1 has the lowest value, num2 has the middle value, and num3 has the highest value
#include <iostream>
using namespace std;
// declare function with reference parameter that with sort numbers
void sortNum(int &, int &, int &);
int main ()
{

[Code]....