C中的Pascal三角形组合

#include <stdio.h>
long factorial(int num)
{
    int counter;
    int fact = 1;
    for (counter = num; counter > 0; counter--) fact *= counter;
    return fact;
}

float combinations(int n, int k)
{
    int numerator = factorial(n);
    int denominator = factorial(k) * factorial(n-k);
    float fraction = numerator/denominator;
    return fraction;
}
int main()
{
    printf("How many rows of Pascal's triangle should I print?t");
    int rows = GetInteger();
    int counter;
    int counter2;
    for (counter = 1; counter <= rows; counter++)
    {
        int y = rows-counter;
        for (; y > 0; y--) printf("   ");
        for (counter2 = 0; counter2 <= counter; counter2++)
                printf("%6.0lu", (long) combinations(counter, counter2));
        printf("n");
    }
}

GetInteger()

scanf()