Thread: Recursive problem with my code

Code:

#include<stdio.h>


int main (void)
{
    int number, checkFactor;
    printf ("Please enter a number between 2 and 1000000.\n\n");
    scanf ("%d", &number);


    if (number < 2 || number > 1000000)
    {
        printf ("\nThis number is not in the domain.\n\n");
        return 0;
    }


    checkFactor = primenesscheck (number);


    if (checkFactor == 1)
    {
            printf ("%d=", number);
            primefactorization (number);
    }


    return 0;
}


int primenesscheck(int number)
{
    int i, checkPrime, notprime;
    for (i=2; i<number; i++)
    {
        if (number % i == 0)
        {
            number = notprime;
            break;
        }
    }


    if (number == notprime)
    {
        printf ("\nThis number is not prime.\n\n");
        checkPrime = 1;
    }


    else
    {
        printf ("\nThis number is prime.\n\n");
        checkPrime = 2;
    }
    return checkPrime;
}


void primefactorization (int number)
{
    int currentfactor,checkingfactor,newnumber;


    for (currentfactor=2;currentfactor<=number;currentfactor++)
    {
        checkingfactor = number % currentfactor;


        if (checkingfactor == 0)
        {
            printf ("(%d)", currentfactor);


            newnumber = number/currentfactor;


            if (newnumber == 1)
            {
                break;
            }


            primefactorization(newnumber);
        }
    }


    return 0;
}

So I'm suffering a problem in my code. When primefactorization is initialised to calculate the product of prime factors of the number (in ascending order), the first couple of values are what I need. However, the program then starts doing stuff that I don't want it to. For instance, if I write 49 as my number, instead of 49=(7)(7), I get 49=(7)(7)(49). Same with any other non prime like 100. Where is my error?

Your loop condition and exit conditions are wrong, the algorithm in general doesn't look right. Why don't you describe what your intent was.

My intent is to create a program that determines whether a number is prime or not, and if it is prime, then calculate the products of prime numbers that compose the non-prime number and list them in ascending order.

The function is executed again but with a different number.