C Program to Print Hollow Diamond Star Pattern

Write a C Program to print a hollow diamond star pattern using nested for loops, while loop, functions, and if-else statements. In this C hollow diamond example, the if statement checks for outer lines and prints stars otherwise, it prints empty spaces to get that hollow shape.

#include<stdio.h>
int main(void)
{
    int i, j, k, rows;
    printf("Enter Diamond Rows =  ");
    scanf("%d", &rows);
    
    printf("Diamond Star Pattern\n");
    for (i = 1 ; i <= rows; i++ )
    {
        for (j = 1 ; j <= rows - i; j++ )
        {
            printf(" ");
        }
        for (k = 1 ; k <= i * 2 - 1; k++ )
        {
            if (k == 1 || k == i * 2 - 1) {
                printf("*");
            }
            else {
                printf(" ");
            }
        }
        printf("\n");
    }
    
    for (i = rows - 1 ; i > 0; i-- )
    {
        for (j = 1 ; j <= rows - i; j++ )
        {
            printf(" ");
        }
        for (k = 1 ; k <= i * 2 - 1; k++ )
        {
            if (k == 1 || k == i * 2 - 1) {
                printf("*");
            }
            else {
                printf(" ");
            }
        }
        printf("\n");
    }
}

Output.

Enter Diamond Rows =  9
Diamond Star Pattern
        *
       * *
      *   *
     *     *
    *       *
   *         *
  *           *
 *             *
*               *
 *             *
  *           *
   *         *
    *       *
     *     *
      *   *
       * *
        *

In this C Hollow Diamond pattern program of stars, we replaced the for loop with a while loop.

#include<stdio.h>
int main(void) {
    int i, j, k, rows;
    printf("Enter Diamond Rows =  ");
    scanf("%d", &rows);
    
    i = 1 ;
    while (i <= rows)
    {
        j = 1 ;
        while (j <= rows - i)
        {
            printf(" ");
            j++;
        }
        k = 1 ;
        while ( k <= i * 2 - 1)
        {
            if (k == 1 || k == i * 2 - 1) {
                printf("*");
            }
            else {
                printf(" ");
            }
            k++;
        }
        printf("\n");
        i++ ;
    }
    
    i = rows - 1 ;
    while ( i > 0)
    {
        j = 1 ;
        while(j <= rows - i )
        {
            printf(" ");
            j++;
        }
        k = 1 ;
        while (k <= i * 2 - 1 )
        {
            if (k == 1 || k == i * 2 - 1) {
                printf("*");
            }
            else {
                printf(" ");
            }
            k++;
        }
        printf("\n");
        i-- ;
    }
}

Enter Diamond Rows =  12
           *
          * *
         *   *
        *     *
       *       *
      *         *
     *           *
    *             *
   *               *
  *                 *
 *                   *
*                     *
 *                   *
  *                 *
   *               *
    *             *
     *           *
      *         *
       *       *
        *     *
         *   *
          * *
           *

C Program to Print Hollow Diamond Star Pattern using do while loop

#include<stdio.h>
int main(void) {
    int i, j, k, rows;
    printf("Enter Diamond Rows =  ");
    scanf("%d", &rows);
    
    i = 1 ;
    do
    {
        j = 1 ;
        do
        {
            printf(" ");
        } while ( j++ <= rows - i) ;
        k = 1 ;
        do
        {
            if (k == 1 || k == i * 2 - 1) {
                printf("*");
            }
            else {
                printf(" ");
            }
        } while ( ++k <= i * 2 - 1);
        printf("\n");
    } while ( ++i <= rows) ;
    
    i = rows - 1 ;
    do
    {
        j = 1 ;
        do
        {
            printf(" ");
        } while(j++ <= rows - i );
        k = 1 ;
        do
        {
            if (k == 1 || k == i * 2 - 1) {
                printf("*");
            }
            else {
                printf(" ");
            }
        } while (++k <= i * 2 - 1 );
        printf("\n");
    } while ( --i > 0);
}

Enter Diamond Rows =  7
       *
      * *
     *   *
    *     *
   *       *
  *         *
 *           *
  *         *
   *       *
    *     *
     *   *
      * *
       *

In this C example, the result function prints the hollow diamond pattern of a given symbol.

#include<stdio.h>
void result(int rows, int i, char ch)
{
    for (int j = 1; j <= rows - i; j++) {
        printf(" ");
    }
    for (int k = 1; k <= i * 2 - 1; k++) {
        if (k == 1 || k == i * 2 - 1) {
            printf("%c", ch);
        } else {
            printf(" ");
        }
    }
    printf("\n");
}
int main(void) {
    int i, rows;
    char ch;
    printf("Enter Symbol =  ");
    scanf("%c", &ch);
    
    printf("Enter Diamond Rows =  ");
    scanf("%d", &rows);
    
    for (i = 1; i <= rows; i++) {
        result(rows, i, ch);
    }
    for (i = rows - 1; i > 0; i--) {
        result(rows, i, ch);
    }
}