C Exercises: Print the Floyd's Triangle

Last update on July 31 2025 05:46:23 (UTC/GMT +8 hours)

22. Floyd's Triangle

Write a program in C to print Floyd's Triangle.
The Floyd's triangle is as below :

This C program prints Floyd's Triangle, a triangular array of binary numbers (0s and 1s). The program prompts the user for the number of rows and then generates the triangle by alternating between 0s and 1s in a specific pattern. The resulting triangle is printed row by row, creating a visually distinct pattern with each row having an increasing number of elements.

Visual Presentation:

Sample Solution:

C Code:

#include <stdio.h> // Include the standard input/output header file.

void main()
{
    int i, j, n, p, q; // Declare variables to store input and control loop indices.

    printf("Input number of rows : "); // Prompt the user for input.
    scanf("%d", &n); // Read the value of 'n' from the user.

    for (i = 1; i <= n; i++) // Loop for the number of rows.
    {
        if (i % 2 == 0) // Check if 'i' is even.
        {
            p = 1;
            q = 0;
        }
        else // If 'i' is odd.
        {
            p = 0;
            q = 1;
        }

        for (j = 1; j <= i; j++) // Loop for each element in the row.
        {
            if (j % 2 == 0) // Check if 'j' is even.
                printf("%d", p); // Print 'p' if 'j' is even.
            else
                printf("%d", q); // Print 'q' if 'j' is odd.
        }

        printf("\n"); // Move to the next line after printing a row.
    }
}

Output:

Input number of rows : 5                                                                                      
1                                                                                                             
01                                                                                                            
101                                                                                                           
0101                                                                                                          
10101

Flowchart:

For more Practice: Solve these Related Problems:

Write a C program to print Floyd's Triangle and then reverse the order of numbers in each row.
Write a C program to display Floyd's Triangle with alternating row alignments (left and right).
Write a C program to print Floyd's Triangle and calculate the sum of each row.
Write a C program to generate Floyd's Triangle recursively.

Go to:

PREV : Sum of Series [9 + 99 + 999 + …].
NEXT : Sum of Series [ 1+x+x^2/2!+x^3/3!+....].

C Programming Code Editor:

Have another way to solve this solution? Contribute your code (and comments) through Disqus.