Example: Pascal's Triangle using nCr in C

// Pascal's Triangle using nCr
#include <stdio.h>

// Function to calculate factorial
long long factorial(int n) {
    long long res = 1;
    for (int i = 2; i <= n; i++) {
        res *= i;
    }
    return res;
}

// Function to calculate nCr
long long nCr(int n, int r) {
    if (r < 0 || r > n) {
        return 0; // Invalid combination
    }
    return factorial(n) / (factorial(r) * factorial(n - r));
}

int main() {
    int rows = 5; // Number of rows to generate

    printf("Pascal's Triangle (nCr approach):\n");
    // Step 1: Iterate through each row
    for (int i = 0; i < rows; i++) {
        // Step 2: Print leading spaces for triangular shape
        for (int space = 0; space < rows - i - 1; space++) {
            printf(" ");
        }
        // Step 3: Iterate through each element in the current row
        for (int j = 0; j <= i; j++) {
            printf("%lld ", nCr(i, j)); // Calculate and print nCr
        }
        printf("\n"); // Move to the next line for the next row
    }
    return 0;
}