Top Down Triangle Printing In C

A triangle with one of its angle 90° is called right triangle. We shall now see how to print stars *, in right triangle shape, but upside down on y axis.

Algorithm

Algorithm should look like this −

Step 1 - Take number of rows to be printed, n.
Step 2 - Make outer iteration I for n times to print rows
Step 3 - Make inner iteration for J to I
Step 3 - Print "*" (star)
Step 4 - Print NEWLINE character after each inner iteration
Step 5 - Return

Pseudocode

We can derive a pseudocode for the above mentioned algorithm, as follows −

procedure topdown_triangle

   FOR I = 1 to N DO
      FOR J = 1 to I DO
         PRINT "*" 
      END FOR
      PRINT NEWLINE
   END FOR

end procedure

Implementation

Implementation of right triangle in C is as follows −

#include <stdio.h>

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

   n = 5;

   for(i = 0; i < n; i++) {
      for(j = 0; j<i; j++)
         printf("  "); 

      for(j = i; j < n; j++)
         printf(" *");

      printf("\n");
      
   }
   
   return 0;
}

The output should look like this −

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