Modifying Code to handle uppercase and special symbols

[Etain]

My code is currently reads in a string of lower case letters, identifying the occurrence of each letter.

#include <stdio.h>
#include <string.h>
 
int main()
{
   char string[256];
   int y = 0, num[26] = {0};
 
   printf("Please enter the required string\n");
   fgets(string, 256, stdin);


 
   while (string[y] !='\0')
   {
        if (string[y] >= 'a' && string[y] <= 'z' ) 
        num[string[y]-'a']++;
 
      y++;
   }
 
   for ( y = 0 ; y < 26 ; y++ )
   {
        if( num[y] != 0 )
        printf("%c occurs %d times in the entered string.\n",y+'a',num[y]);
   }
 
   return 0;
}

My issue is that I want my code to read uppercase and special symbols. showing the occurrence of both.

I have an idea:

else if(str[x] >= 'a' && str[x] <= 'z');
    
else if(str[x] >= '0' && str[x] <= '9');

However I struggle to implement it, any help would be appreciated.

[Matticus]

If you're just counting the occurrences of letters, then perhaps you should consider a loop that makes all the letters lowercase using "tolower()" before you start counting.

If by "special characters" you mean digits (as indicated in your idea), check out the "isdigit()" function. In that link, on the "ctype.h" list on the bottom left of the screen, you can see other functions that check types of characters, special and otherwise.

[Malcolm McLean]

Assuming that strings are long and you know that chars are always 0-127 (ASCII) or 0-256 (extended ASCII), the first thing to do is to get a histogram of the string. That's a separate function.
Now you want to count characters in each class. So a-z and A-Z will always be in range (assuming ASCII) and 0-9 will always be in range (by C standard). But "special characters" could be anything. Do you include control characters, extended ASCII characters, non-alphabetical extended ASCII characters ?
Either use the isxxx (isupper, islower, isdigit, isgraph etc) functions in ctype.h, or just build a list of your own, by hand. Then loop over the histogram, checking on the index and summing if positive.

[Jimmy]

Assuming that strings are long and you know that chars are always 0-127 (ASCII) or 0-256 (extended ASCII), the first thing to do is to get a histogram of the string. That's a separate function.
Now you want to count characters in each class. So a-z and A-Z will always be in range (assuming ASCII) and 0-9 will always be in range (by C standard). But "special characters" could be anything. Do you include control characters, extended ASCII characters, non-alphabetical extended ASCII characters ?
Either use the isxxx (isupper, islower, isdigit, isgraph etc) functions in ctype.h, or just build a list of your own, by hand. Then loop over the histogram, checking on the index and summing if positive.

I'd say always go with a library function if you can. Better to abstract that stuff away.