[C] Draw Pascal's triangle

/*
           1
         1   1
       1   2   1
     1   3   3    1
   1  4    6   4   1
 1  5   10   10  5   1
*/

#include<stdio.h>
int main()
{
    int rows,coef=1,space,i,j;
    printf("Enter number of rows: ");
    scanf("%d",&rows);
    for(i=0;i<rows;i++)
    {
        for(space=1;space<=rows-i;space++)
        printf("  ");
        for(j=0;j<=i;j++)
        {
            if (j==0||i==0)
                coef=1;
            else
               coef=coef*(i-j+1)/j;
            printf("%4d",coef);
        }
        printf("\n");
    }
}