Pascal's triangle

C++ Program to Draw Pascal's triangle as below:

           1
         1   1
       1   2   1
     1   3   3    1
   1  4    6   4   1
 1  5   10   10  5   1 

#include <iostream>
using namespace std;
int main()
{
    int rows,coef=1,space,i,j;
    cout<<"Enter number of rows: ";
    cin>>rows;
    for(i=0;i<rows;i++)
    {
        for(space=1;space<=rows-i;space++)
        cout<<"  ";
        for(j=0;j<=i;j++)
        {
            if (j==0||i==0)
                coef=1;
            else
               coef=coef*(i-j+1)/j;
            cout<<"    "<<coef;
        }
        cout<<endl;
    }
}