#include <stdio.h>

/*******************************************************************************
*NOTICE:                                                                       *
*This code is believed by the author to be bug free.  You are free to use and  *
*modify this code with the understanding that any use, either direct or        *
*derivative, must contain acknowledgement of its author and source.  The author*
*makes no warranty of any kind, expressed or implied, of merchantability or    *
*fitness for a particular purpose.  The author shall not be held liable for any*
*incidental or consequential damages in connection with or arising out of the  *
*furnishing, performance, or use of this software.  This software is not       *
*authorized for use in life support devices or systems.                        *
********************************************************************************/

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

  if(argc != 3){
  printf("\n%s%s%s\n%s\n%s\n",
"Usage: ",argv[0]," infile outfile", 
"The probability of occurrence of upper and lower case letters",
"in infile is counted and written to outfile");
  exit(1);      }

  if((ifp = fopen(argv[1],"r")) == NULL)
    printf("Input open failed");

  if((ofp = fopen(argv[2],"w")) == NULL)
    printf("output open failed");

  for(i=0; i<26; i++)
    letter[i] = 0;
  num = 0;

  while((c=getc(ifp)) != EOF)
   {
    if(c >= 'A' && c <= 'Z')
      letter[c-'A']++;
    if(c >= 'a' && c <= 'z')
      letter[c-'a']++;
    num++;
   }

   for(i=0; i<26; i++)
    {
    prob[i] = (float) letter[i] / (float) num;
    fprintf(ofp,"%c  %f\n",'A'+i,prob[i]);
    }
}