jfile.c
=======
/* Count uppercase letters in a file */

#include <stdio.h>

main(int argc, char *argv[])
{
  int	c, i, letter[26];
  FILE	*ifp, *ofp;

  if (argc != 3) {
     printf("\n%s%s%s\n\n%s\n%s\n\n",
	"Usage: ", argv[0], " infile outfile",
	"The uppercase letters in infile will be counted.",
	"The results will be written in outfile.");
     exit(1);
  }
  ifp = fopen(argv[1], "r");
  ofp = fopen(argv[2], "w");
  for (i = 0; i < 26; ++i)  /* initialize array to zero */
	letter[i] = 0;
  while ((c = getc(ifp)) != EOF)
     if (c >= 'A' && c <= 'Z')  /* find uppercase letters */
	++letter[c - 'A'];
  for (i = 0; i < 26; ++i) {   /* print results */
     if (i % 6 == 0 )
	putc('\n', ofp);
     fprintf(ofp, "%c:%5d     ", 'A' + i, letter[i]);
  }
  putc('\n', ofp);
}

Output:

A:    4     B:    2     C:   12     D:    2     E:    0     F:    4     
G:   10     H:    0     I:    2     J:    0     K:    0     L:    8     
M:    2     N:    0     O:    4     P:    4     Q:    0     R:    4     
S:    6     T:    2     U:    0     V:    0     W:    0     X:    0     
Y:    0     Z:    0