C program to print rhombus or parallelogram star pattern

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

Enter number of rows: 5

    *****
   *****
  *****
 *****
*****

Required knowledge

Basic C programming, For loop, Nested Loop

Logic to print rhombus star pattern

    *****
   *****
  *****
 *****
*****

Before I decode the logic of this pattern, have a close look of the pattern. Place your mouse cursor on to the pattern, to count spaces. Try to decode the logic of given pattern.

If you remove trailing spaces the pattern becomes a simple square star pattern of N rows and columns. You only need to add logic of printing spaces with the existing logic of square star pattern.

The pattern consists N - i spaces per row (where i is the current row number).

Step by step descriptive logic to print rhombus star pattern

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

Program to print rhombus star pattern

/**
 * C program to print Rhombus star pattern series
 */

#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 after spaces */
        for(j=1; j<=rows; j++)
        {
            printf("*");
        }

        /* Move to the next line */
        printf("\n");
    }

    return 0;
}

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

Logic to print parallelogram star pattern

    ********************
   ********************
  ********************
 ********************
********************

Logic to print parallelogram star pattern is same as of rhombus star pattern. With few modification you can code it out.

Step by step descriptive logic to print parallelogram star pattern.

1. Input rows and columns from user. Store it in a variable say rows and columns.
2. To iterate through rows, run an outer loop from 1 to rows. Define a loop with structure for(i=1; i<=rows; i++).
3. Run an inner loop to print space from 1 to rows - i with loop structure for(j=1; j<=rows - i; j++).
4. To print stars run another inner loop after printing space. Run a loop from 1 to columns. Define a loop with structure for(j=1; j<=columns; j++).

Program to print parallelogram star pattern

/**
 * C program to print Rhombus star pattern series
 */

#include <stdio.h>

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

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

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

        /* Print stars after spaces */
        for(j=1; j<=columns; j++)
        {
            printf("*");
        }

        /* Move to the next line */
        printf("\n");
    }

    return 0;
}

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