Thread: Need help on factoring program.

I'm diving into C++ and after going through some the tutorials on CProgramming.com, I saw a challenge to make a program factor a number using recursion. So I had to do it. The program through each instance finds the right factor and the right number of loops, but and the end when I print the linked list out it's all the last value I found. I feel like I'm close on this and need some help.

Big thanks in advance!

Code:

// class1.cpp: implementation of the class1 class.
//
//////////////////////////////////////////////////////////////////////

#include "class1.h"
#include "iostream.h"

//////////////////////////////////////////////////////////////////////
// Construction/Destruction
//////////////////////////////////////////////////////////////////////

class1::class1()
{

}

class1::~class1()
{

}

struct fact {
	int val;
	fact *next;
};

void GO(int *srcNum, fact *srcFact) {
	bool chgsrc;
	fact *tmpFact;
	tmpFact=new fact;

	srcFact->next=new fact;
	srcFact=srcFact->next;
	srcFact->next=0;
	srcFact->val=0;

	chgsrc = 1;

	if (*srcNum != 1) {
		if (*srcNum % 2 == 0) {
			srcFact->val=2;
			if (chgsrc) {
				*srcNum=*srcNum / 2;
				cout<<"- "<<*srcNum<<endl;
				cout<<srcFact->val<<endl;
				cout<<srcFact<<endl;
				//tmpFact=tmpRoot;
				//if(tmpFact!=0)
				//{
					//while(tmpFact->next!=0)
					//{
						//cout<<tmpFact->val<<" - "<<tmpFact<<endl;
						//tmpFact=tmpFact->next;   
					//}
					//cout<<tmpFact->val<<endl;
				//}

				cout<<endl;
				chgsrc = 0;
			}
		}

		if (*srcNum % 3 == 0) {
			srcFact->val=3;
			if (chgsrc) {
				*srcNum=*srcNum / 3;
				cout<<"- "<<*srcNum<<endl;
				cout<<srcFact->val<<endl;
				cout<<srcFact<<endl;
				cout<<endl;
				chgsrc = 0;
			}
		}

		if (*srcNum % 5 == 0) {
			srcFact->val=5;
			if (chgsrc) {
				*srcNum=*srcNum / 5;
				cout<<"- "<<*srcNum<<endl;
				cout<<srcFact->val<<endl;
				cout<<srcFact<<endl;
				cout<<endl;
				chgsrc = 0;
			}
		}

		if (*srcNum % 7 == 0) {
			srcFact->val=7;
			if (chgsrc) {
				*srcNum=*srcNum / 7;
				cout<<"- "<<*srcNum<<endl;
				cout<<srcFact->val<<endl;
				cout<<srcFact<<endl;
				cout<<endl;
				chgsrc = 0;
			}
		}
	}

	if (srcFact->val != 0) {
		GO(srcNum, srcFact->next);
	} else {
		//srcFact->val = *srcNum;
	}

};


int main() {
	fact *root;
	fact *nxtFact;
	int numtochk;

	numtochk = 30;

	nxtFact = new fact;
	root=new fact;
	root->next=0;
	root->val=1; //Make this 1 because a factorial is atleast that number times 1.

	nxtFact = root;

	GO(&numtochk, nxtFact);

	
	//NOW I WANT TO SEE ALL MY VALUES
	nxtFact=root; //Lets go back to the beginning
	if(nxtFact!=0)
	{
		while(nxtFact->next!=0)
		{
			cout<<nxtFact->val<<" - "<<nxtFact<<endl;
			nxtFact=nxtFact->next;   
		}
		cout<<nxtFact->val<<endl;
	}

	return 0;
}

The final if statement in the GO function, I had mistyped. It should be:

Code:

	if (srcFact->val != 0) {
		GO(srcNum, srcFact);
	} else {
		//srcFact->val = *srcNum;
	}

The main problem was with the if code block for each base prime. Amongst other small corrections I made in the code the correct if statement should be:

Code:

if (*srcNum % 2 == 0) {
		if (chgsrc) {
			srcFact->val=2;
			*srcNum=*srcNum / 2;
			chgsrc = 0;
		}
	}

instead of

Code:

if (*srcNum % 2 == 0) {
		srcFact->val=2;
		if (chgsrc) {
			*srcNum=*srcNum / 2;
			chgsrc = 0;
		}
	}