Example: Butterfly Pattern Printer in C

// Butterfly Pattern Printer
#include <stdio.h>

int main() {
    int n, i, j;

    // Step 1: Prompt user for input
    printf("Enter the number of rows for one half of the butterfly (e.g., 4 for a medium size): ");
    scanf("%d", &n);

    // Step 2: Print the upper half of the butterfly
    // This loop iterates from row 1 to 'n' (the widest point)
    for (i = 1; i <= n; i++) {
        // Left wing stars: Prints 'i' stars, increasing with each row
        for (j = 1; j <= i; j++) {
            printf("*");
        }

        // Spaces in between: Prints 2 * (n - i) spaces, decreasing with each row
        for (j = 1; j <= 2 * (n - i); j++) {
            printf(" ");
        }

        // Right wing stars: Prints 'i' stars, increasing with each row
        for (j = 1; j <= i; j++) {
            printf("*");
        }
        printf("\n"); // Move to the next line after each row
    }

    // Step 3: Print the lower half of the butterfly
    // This loop iterates from row 'n-1' down to 1 (mirroring the upper half)
    for (i = n - 1; i >= 1; i--) {
        // Left wing stars: Prints 'i' stars, decreasing with each row
        for (j = 1; j <= i; j++) {
            printf("*");
        }

        // Spaces in between: Prints 2 * (n - i) spaces, increasing with each row
        for (j = 1; j <= 2 * (n - i); j++) {
            printf(" ");
        }

        // Right wing stars: Prints 'i' stars, decreasing with each row
        for (j = 1; j <= i; j++) {
            printf("*");
        }
        printf("\n"); // Move to the next line after each row
    }

    return 0;
}