#include <stdio.h>

int main()
{
  int i, j, num_lines;
  int middle_spaces = 0;

  //gets user input
  printf("Please enter an integer: ");
  scanf("%d", &num_lines);

  //this loop prints most of the triangle except the last line
  for (i = (num_lines-1); i > 0; i--)
    {
      //prints the empty spaces before the first * on every line
      for (j = i; j > 0; j--)
	{
	  printf(" ");
	}

      //prints the first star
      printf("*");

      //if its the top row, print new line and go to next row
      if(middle_spaces == 0)
	{
	  printf("\n");
	  middle_spaces = 1;
	  continue;
	}

      //prints the spaces inside the triangle
      for (j = middle_spaces; j > 0; j--)
	{
	  printf(" ");
	}

      //prints the 2nd "*"
      printf("*\n");
      middle_spaces +=2;
    }

  //prints the last line of the triangle
  for (i = ((num_lines*2) - 1); i > 0; i--)
    {
      printf("*");
    }

  printf("\n");

  return 0;
}