C program to print hollow rhombus, parallelogram star pattern

Write a C program to print hollow rhombus star series pattern using for loop. How to print hollow rhombus or parallelogram star pattern in C programming. Logic to print empty rhombus or parallelogram star pattern series in C programming.

Example

Input

Input number of rows: 5

Output

Required knowledge

Basic C programming, If else, For loop, Nested loop

Must know -

Logic to print hollow rhombus star pattern

Step by step descriptive logic to print rhombus star pattern.

  1. Input number of rows to print from user. Store it in a variable say rows.
  2. To iterate through rows, run an outer loop from 1 to rows. Define an outer loop with structure for(i=1; i<=rows; i++).
  3. To print trailing spaces, run an inner loop from 1 to rows - i. Run a loop with structure for(j=1; j<=rows - i; j++). Inside this loop print blank space.
  4. To print stars, run another inner loop from 1 to rows with structure for(j=1; j<=rows; j++).
  5. Inside this loop print star for first or last row, and for first or last column otherwise print spaces. Which is print stars only when i==1 or i==rows or j==1 or j==rows.
  6. After printing all columns of a row move to next line i.e. print new line.

Program to print hollow rhombus star pattern

/**
 * C program to print hollow rhombus star pattern
 */

#include <stdio.h>

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

    /* Input number of rows from user */
    printf("Enter rows : ");
    scanf("%d", &rows);


    for(i=1; i<=rows; i++)
    {
        /* Print trailing spaces */
        for(j=1; j<=rows-i; j++)
        {
            printf(" ");
        }


        /* Print stars and center spaces */
        for(j=1; j<=rows; j++)
        {
            if(i==1 || i==rows || j==1 || j==rows)
                printf("*");
            else
                printf(" ");
        }

        printf("\n");
    }

    return 0;
}

Output

Enter rows: 5
    *****
   *   *
  *   *
 *   *
*****

Hurray!!! we printed a hollow rhombus star pattern. What's next now? You can modify the above logic to work for parallelogram. Let us write C code to print hollow parallelogram.

Program to print hollow parallelogram star pattern

/**
 * C program to print hollow parallelogram star pattern
 */

#include <stdio.h>

int main()
{
    int i, j, rows, columns;

    /* Input number of row and column */
    printf("Enter rows : ");
    scanf("%d", &rows);
    printf("Enter columns: ");
    scanf("%d", &columns);

    for(i=1; i<=rows; i++)
    {
        /* Print trailing spaces */
        for(j=1; j<=rows-i; j++)
        {
            printf(" ");
        }

        /* Print stars and center spaces */
        for(j=1; j<=columns; j++)
        {
            if(i==1 || i==rows || j==1 || j==columns)
                printf("*");
            else
                printf(" ");
        }

        printf("\n");
    }

    return 0;
}

Output

Enter rows: 5
Enter columns: 10
    **********
   *        *
  *        *
 *        *
**********

Happy coding 😉

About Pankaj

Pankaj Prakash is the founder, editor and blogger at Codeforwin. He loves to learn new techs and write programming articles especially for beginners. He works at Vasudhaika Software Sols. as a Software Design Engineer and manages Codeforwin. In short Pankaj is Web developer, Blogger, Learner, Tech and Music lover.

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