The concept of recursion is actually simple but implementing it is more challenging than you might think. Recursion works by creating a function that calls itself until it hits a base case to end/breakout of the recursion function. Along with the base case, it has another case that slowly leads to the base case.

A simple implementation of this can be seen with a function that gets the factorial value given a certain number.

Here is what that function looks like:

// Factorial function using recursion
int factorial(int n)
{
    // Base case for when the number given is 0
    if (n == 0)
    {
        return 1;
    }
 
    // Takes the given value and multiplies it by the previous factorial value
    else
    {
        // Function calls itself (calls n-1) until it reaches the base case (0)
        return n * factorial(n - 1);
    }
}

As you can see the function starts with the base case and then actually implements the logic for the function. Lets give it a value.