I'm trying to figure out how to write a program in C that will take in characters, typed or specified by a file and count their occurences and print out how many each are.

I am not too clear how to do this. I am thinking of an array of char that index each ascii value and check each character agains the ascii array if there is increment the number of the ascii at that character index. But the next loop around wouldn't that change my ascii number and now i have nothing to check against when new inputs of the same character and ascii values are found.

Does anyone understand what I'm trying to explain? I have no programming level, in C. This is my introduction too it.

If anyone have a suggestion on how i can achieve this task please give me some advice.

Thanks ahead,
Ck

A brute force way to do this is to define a 26 element integer array named count[] and initialize all elements to 0. Now suppose all of your character data is stored in a string named data[]. Code similar to this should work:

   char c;
   int count[26];
   int i = 0;
   int index;

   memset(&count, 0, sizeof(int) * 26); /* Init array to zero */

   while (data[i] != null) /* Look at each character */
   {
      c = toupper(data[i]); /* Make it uppercase */
      if (c >= 'A' && c <= 'Z') /* Is it an alpha character? */
      {
         index = (int) (c - 'A'); /* Make an index into the array */
         count[index]++; /* Increment its count */
      }
      i++; /* Look at next letter */
   }

While my C is rusty, this should give you an idea. For example, if the first letter in data[0] is 'd', the call to toupper() makes it 'D'. The next line checks to insure that it's a letter. The next line takes the letter D (which is ASCII code 68) and subtracts the letter 'A' (ASCII code 65) from it, which assigns 3 into index. The next statement increments that count in the array. A little thought will show:

   count[0] = 'A'
   count[1] = 'B'
   count[2] = 'C'
   count[3] = 'D'

and so on. If you work out a short sentence in the data[] array, you'll find you end up with a count of the number of occurrences of each letter.

Dr. Purdum