Using pointers to calculate the arithmetic mean from string-CodePudding

I am struggling with the pointer exercises for my C programming course. I am asked to calculate the arithmetic mean from comma separated list of integers using the prototype float mean(char *list); and strtok function. However, I can not get my function to work properly. Here is my proposed solution;

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

float mean(char *list);

float mean(char *list) {

    const char sep[] = ",";
    char *token;

    token = strtok(list, sep);
    int8_t value = atoi(token);
    int8_t total = value;
    int8_t count = 1;

    while(token != NULL) {
        token = strtok(NULL, sep);
        value = atoi(token);
        total = total   value;
        count = count   1;
    }

    double mean;
    mean = total/count;
    return mean;
}

CodePudding user response：

In your while loop, you are updating the token at the start of the loop, so in the next line you should check if the token has become NULL or not - but you are not checking that. Here is the code:

float mean(char *list) {
  const char sep[] = ",";
  char *token;

  token = strtok(list, sep);
  int8_t value = atoi(token);
  int8_t total = value;
  int8_t count = 1;

  while(token != NULL) {
    token = strtok(NULL, sep);
    if (token == NULL) break;
    value = atoi(token);
    total = total   value;
    count = count   1;
  }

  double mean;
  mean = total/count;
  return mean;
}