Question

I know my way around ruby pretty well and am teaching myself C starting with a few toy programs. This one is just to calculate the average of a string of numbers I enter as an argument.

#include <stdio.h>
#include <string.h>

main(int argc, char *argv[])
{
   char *token;
   int sum = 0;
   int count = 0;
   token = strtok(argv[1],",");
   while (token != NULL)
   {
     count++;
     sum += (int)*token;
     token = strtok(NULL, ",");
   }

 printf("Avg: %d", sum/count);
 printf("\n");
 return 0;
}

The output is:

mike@sleepycat:~/projects/cee$ ./avg 1,1
Avg: 49

Which clearly needs some adjustment.

Any improvements and an explanation would be appreciated.

Answer 1

In this line: sum += (int)*token;
Casting a char to an int takes the ASCII value of the char. for 1, this value is 49.

Use the atoi function instead:

sum += atoi(token);

Note atoi is found in the stdlib.h file, so you’ll need to #include it as well.