Triangle number pattern using 0, 1 in C – 3

Write a C program to print the given triangle number pattern using 0, 1. How to print the given triangle number pattern with 0, 1 using for loop in C programming. Logic to print the given triangle number pattern using C program.

Input N: 5

1
01
010
1010
10101

Required knowledge

Basic C programming, If else, Loop

Logic to print the given triangle number pattern

1
01
010
1010
10101

1. The pattern consists of N rows (where N is the total number of rows to be printed). Hence the outer loop formation to iterate through rows will be for(i=1; i<=N; i++).
2. Here each row contains exactly i number of columns (where i is the current row number). Loop formation to iterate through columns will be for(j=1; j<=i; j++).
3. Once you are done with the loop formation. Have a closer look to the pattern. If you view the pattern as

   1
   2 3
   4 5 6
   7 8 9 10
   11 12 13 14 15

   you can easily print the final pattern. Where for each odd integers 1 gets printed and for each even integers 0 gets printed. Therefore to get such pattern we need to check a simple condition if(k % 2 == 1) before printing 1s or 0s (where k represents the current integer).

Lets, code down the solution in C program.

Program to print the given triangle number pattern

/**
 * C program to print the given number pattern
 */

#include <stdio.h>

int main()
{
    int i, j, k, N;

    printf("Enter N: ");
    scanf("%d", &N);

    // k represents the current integer
    k = 1;

    for(i=1; i<=N; i++)
    {
        for(j=1; j<=i; j++)
        {
            // Print 1 if current integer k is odd
            if(k % 2 == 1)
            {
                printf("1");
            }
            else
            {
                printf("0");
            }

            k++;
        }

        printf("\n");
    }

    return 0;
}

Enter N: 5
1
01
010
1010
10101

You can also print the given number pattern without using if else. Below is a simple but tricky program to print the same number pattern. It uses bitwise operator to check even odd.

Program to print the given number pattern without using if

/**
 * C program to print the given number pattern
 */

#include <stdio.h>

int main()
{
    int i, j, k, N;

    printf("Enter N: ");
    scanf("%d", &N);

    // k represents the current integer
    k = 1;

    for(i=1; i<=N; i++)
    {
        for(j=1; j<=i; j++)
        {
            printf("%d", (k & 1));

            k++;
        }

        printf("\n");
    }

    return 0;
}

Note: You can also obtain the reverse of the given pattern

0
10
101
0101
01010

You just need to swap the two printf(); statements. Means just replace the printf(“1”); with printf(“0”);.
Happy coding 😉