Character triangle

triangle.c

#include <stdio.h>
#include <stdlib.h>

int main(void)
{
  int chars_in_line = 7;
  char current_letter = 65; 	/* ASCII A */
  int current_chars_in_line = chars_in_line;

  for(int i = 0; i < chars_in_line; i++)
    {
      printf("%*s", chars_in_line - current_chars_in_line, "");
      for(int i = 0; i < current_chars_in_line; i++)
	{
	  printf("%c", current_letter++);
	  if (current_letter == 91) /* if we got to Z start from A again */
	    current_letter = 65;
	}
      printf("\n");
      current_chars_in_line--;
    }

  return EXIT_SUCCESS;
}

Output:

$ ./triangle
ABCDEFG
 HIJKLM
  NOPQR
   STUV
    WXY
     ZA
      B