Number pattern 40 in C

Write a C program to print the given number pattern using loop. How to print the given number pattern using loop in C programming. Logic to print the given number pattern using C program.

Input N: 5

1        1
12      21
123    321
1234  4321
1234554321

Required knowledge

Basic C programming, Loop

Logic to print the given pattern

1        1
12      21
123    321
1234  4321
1234554321

On first look the pattern may seem little difficult to print out. Lets make things little easier and dissect the given pattern in two internal parts.

1
12
123
1234
12345

1
21
321
4321
54321

Between these two patterns spaces are printed in decreasing order i.e first row contains 8, second row contains 6 spaces and so on last row contains 0 spaces. Loop formation to print spaces will be for(j=i*2; j<N*2; j++).
Loop to print the above two pattern will be similar and simple. It has also been discussed in one of my earlier post. Lets combine everything in single program.

Program to print the given pattern

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

#include <stdio.h>

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

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

    for(i=1; i<=N; i++)
    {
        // Prints first part of pattern
        for(j=1; j<=i; j++)
        {
            printf("%d", j);
        }

        // Prints spaces between two parts
        for(j=i*2; j<N*2; j++)
        {
            printf(" ");
        }

        // Prints second part of the pattern
        for(j=i; j>=1; j--)
        {
            printf("%d", j);
        }

        printf("\n");
    }

    return 0;
}

Enter rows: 5
1        1
12      21
123    321
1234  4321
1234554321

Happy coding 😉