C program to print pascal triangle

Example

Input

Input rows: 5

Output

    1
   1 1
  1 2 1
 1 3 3 1
1 4 6 4 1

Pascal Triangle

Pascal triangle is a triangular number pattern named after famous mathematician Blaise Pascal.

For example Pascal triangle with 6 rows.

/**
 * C program to print Pascal triangle up to n rows
 */

#include <stdio.h>

/* Function definition */
long long fact(int n);

int main()
{
    int n, k, num, i;
    long long term;

    /* Input number of rows */
    printf("Enter number of rows : ");
    scanf("%d", &num);

    for(n=0; n<num; n++)
    {
        /* Prints 3 spaces */
        for(i=n; i<=num; i++)
            printf("%3c", ' ');

        /* Generate term for current row */
        for(k=0; k<=n; k++)
        {
            term = fact(n) / (fact(k) * fact(n-k));

            printf("%6lld", term);
        }

        printf("\n");
    }

    return 0;
}

/**
 * Function to calculate factorial
 */
long long fact(int n)
{
    long long factorial = 1ll;
    while(n>=1)
    {
        factorial *= n;
        n--;
    }

    return factorial;
}

/*
Output :

Enter number of rows : 10
                         1
                       1   1
                     1   2   1
                   1   3   3   1
                 1   4   6   4   1
               1   5  10  10   5   1
             1   6  15  20  15   6   1
           1   7  21  35  35  21   7   1
         1   8  28  56  70  56  28   8   1
       1   9  36  84 126 126  84  36   9   1
*/