Help with a simple C programming exercise

I'm new to C programming, having a bit of difficulty with a programming exercise, I'm sure this is simple for anyone who knows C, unfortunately you have to play by the rules of the exercise.

Here's the exercise:

Have a program request the user to enter an uppercase letter. Use nested loops to produce a pyramid pattern like this:

    A 

   ABA

  ABCBA

 ABCDCBA

ABCDEDCBA

The pattern should extend to the character entered. For example, the preceding pattern w开发者_开发技巧ould result from an input value of E. Hint: Use an outer loop to handle the rows. Use three inner loops in a row, one to handle the spaces, one for printing letters in ascending order, and one for printing letters in descending order.

So I got this far:

#include <stdio.h>

int main(void) {

 int rows;
 int spaces;

 char asc;
 char desc;
 char input;

 printf("Please enter an uppercase letter: ");
 scanf("%c", &input);

 for (rows = 'A'; rows <= input; rows++) {
  for (spaces = input; spaces > rows; spaces--) {
   printf(" ");
  }
  for (asc = 'A'; asc <= rows; asc++) {
   printf("%c", asc);
  }
  for (desc = asc - 2; desc >= rows; desc--) {
   printf("%c", desc);
  }
  printf("\n");
 }
 return 0;
}

You're very close:

for (desc = asc - 2; desc >= 'A'; desc--) {

Note that after the second inner loop, asc is rows + 1. You're then initializing desc to rows - 1. You should be able to see why >= rows is wrong, and will result in no iterations.

The correct condition is simply >= 'A'.