Simplifying and Fixing code for Finding nth Row of Pascal Triangle

[LuXian]

I'm a noob in programming and can't simplify this messy code or even fix the error saying:error C2086: 'b' : redefinition. Please help me. Here's the code:

#include<iostream>

using namespace std;

int main()

{

    int c,b,row,ent,factorial=1,s,d,nth;

    cout<<" Enter Row:  ";

    cin>>row;

    for(int a=1;a<=row;a++)

    {

        s=factorial*a;

    }

	cout<<" Enter Entry: ";

	cin>>ent;
 
	for(int f=1;f<=ent;f++)

    {

        d=factorial*f;

    }

	c=s-d;

	for(int b=1;b<=c;b++)

	{
	
		c=factorial*b;

	}

	nth=s/(d*c);

	cout<<" The nth row is "<< nth;

    return 0;

}