C Program to print patterns (Rectangle and Pyramid)

We are using C to print the patterns in this blog.

These kinds of pattern programs can be solved easily using for loop condition.

1) Hollow Rectangle:

#include <stdio.h>
void hollowRectangle(int n, int m)
{

    int i, j;

    for (i = 1; i <= n; i++)
    {
        for (j = 1; j <= m; j++)
        {
            if (i==1 || i==n || j==1 || j==m)
                printf("* ");
            else
                printf("  ");
        }
      printf("\n");
    }
}

int main()

{
    int rows, columns;
    printf("\n Enter the number of rows : ");
    scanf("%d", &rows);
    printf("\n Enter the number of columns : ");
    scanf("%d", &columns);
    printf("\n");

    hollowRectangle(rows, columns);

    return 0;
}
Output:
Enter the number of rows : 5
Enter the number of columns : 5
* * * * *
*       *
*       *
*       *
* * * * * 

2) Half Pyramid Star Pattern:

#include <stdio.h>
int main()
{
    int size;
    printf("\n Enter size : ");
    scanf("%d", &size);

    for(int i = 1; i<=size; i++)
    {
        for(int j = 1; j <= i; j++)
        {
            printf("*");
        }
        printf("\n");
    }
    return 0;
}
Output:
Enter the size: 5
*
**
***
****
*****

3) Inverted Half pyramid:

#include <stdio.h>
int main()
{
    int size;
    printf("\n Enter size : ");
    scanf("%d", &size);

    for(int i = size; i >= 1; i--)
    {
        for(int j = 1; j <= i; j++)
        {
            printf("*");
        }
        printf("\n");
    }
    return 0;
}
Output:
Enter size: 5
*****
****
***
**
** * * * *

4) Full pyramid Star pattern:

#include <stdio.h>
int main() {
   int i, space, rows, k = 0;
   printf("Enter the number of rows: ");
   scanf("%d", &rows);
   for (i = 1; i <= rows; ++i, k = 0) {
      for (space = 1; space <= rows - i; ++space) {
         printf("  ");
      }
      while (k != 2 * i - 1) {
         printf("* ");
         ++k;
      }
      printf("\n");
   }
   return 0;
}
Output:
Enter the number of rows: 5
                *
              * * *
            * * * * *
          * * * * * * *
        * * * * * * * * *

5) Inverted Full pyramid of * :

#include <stdio.h>
int main() {
   int rows, i, j, space;
   printf("Enter the number of rows: ");
   scanf("%d", &rows);
   for (i = rows; i >= 1; --i) {
      for (space = 0; space < rows - i; ++space)
         printf("  ");
      for (j = i; j <= 2 * i - 1; ++j)
         printf("* ");
      for (j = 0; j < i - 1; ++j)
         printf("* ");
      printf("\n");
   }
   return 0;
}
Output:
Enter the number of rows:5
* * * * * * * * *
  * * * * * * *
    * * * * *
      * * *
        *

6) Hollow Full Pyramid:

#include <stdio.h>
int main()
{
    int n;
    printf("Enter number: ");
    scanf("%d",&n);
	int i, j, k = 0;
	for (i = 1; i <= n; i++) // row=6
	{
		// Print spaces
		for (j = i; j < n; j++) {
			printf(" ");
		}
		// Print #
		while (k != (2 * i - 1)) {
			if (k == 0 || k == 2 * i - 2)
				printf("*");
			else
				printf(" ");
			k++;
			;
		}
		k = 0;
		printf("\n"); // print next row
	}
	// print last row
	for (i = 0; i < 2 * n - 1; i++) {
		printf("*");
	}
}
Output:
Enter number: 5
    *
   * *
  *   *
 *     *
*       *
*********

Please write comments if you find anything incorrect, or you want to share more information about the topic discussed above.

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