Program to Print Mirrored Hollow Parallelogram in C

Program Description

It is a quadrilateral where both pairs of opposite sides are parallel.

There are six important properties of parallelograms to know

Opposite sides are congruent (AB = DC).
Opposite angels are congruent (D = B).
Consecutive angles are supplementary (A + D = 180°).
If one angle is right, then all angles are right.
The diagonals of a parallelogram bisect each other.
Each diagonal of a parallelogram separates it into two congruent

Algorithm

Accept number of rows and columns from user. Store it in rows and cols variables.
To iterate though rows, run an outer loop with the loop structure should look like for(r=1; r<=rows; r++).
To print space, run an inner loop with loop structure for(c=1; c<r; c++). Inside this loop print single blank space.
Print star to form hollow parallelogram, run another inner loop with the loop structure like for(c=1; c<=cols; c++). Inside this loop, print stars only if r==1 or r==rows or c==1 or c==cols.
After printing all columns of a row, move to next line i.e. print new line.

Example

// C program to print mirrored hollow parallelogram
#include <stdio.h>
int main(){
   int rows,cols,r,c;
   clrscr(); /*Clears the Screen*/
   printf("Please enter the number of Rows: ");
   scanf("%d", &rows);
   printf("\n");
   printf("Please enter the number of Columns: ");
   scanf("%d", &cols);
   printf("\n");
   printf("The Mirrored Hollow Parallelogram is: ");
   printf("\n");
   for(r = 1; r <= rows; r++){
      // Display spaces
      for(c = 1; c < r; c++) {
         printf(" ");
      }
      // Display hollow parallelogram
      for(c = 1; c <= cols; c++) {
         if (r == 1 || r == rows || c == 1 || c == cols) {
            printf("*");
         }
         else {
            printf(" ");
         }
      }
      printf("\n");
   }
   getch();
   return 0;
}

Output

Program to Print Mirrored Hollow Parallelogram in C