you have two problems in your code: the first one is that you have infinite loop in randomgen() function the condition in check against y - y != 9 but the value never update

int randomgen() 
{
    //This creates a variable to store the random number.
    int ran;

    //This creates a LCV for the do loop below and sets it equal to 0.
    int y = 0;

    //This do loop generates the random number.
    do
    {
        //This generates a random time seed.
        srand(time(0));

        //This generates a random number between 1 and 99.
        ran = rand() % 100;

        //This while controls the do loop.
    }while (y != 9);

    //This returns the random number for use in the rest of the program.
    return ran;
}

and the second one is even if you pass the loop in the function you exit main right away because the call to the function randomgen() is with return

if (z < 2)
{
    //This runs the random number generator function.
    return randomgen(); <-- **second problome**

    //This sets the result of the function as the random number.
    randnum = randomgen();

    //This sets the random number to the current number.
    num = randnum;
}