Strtol（）函数基本C

Question

When I am using the strtol() function, when I am trying convert:

2015-08-12

I would like it to fail conversion rather than converting only 2015 ?

int main(int argc, char *argv[])
{
     printf("Number of arguments: %d\n", argc);


  int i = 1;
  while (argc > i)
  {

  char *p;
  int num;

  errno = 0;
  long conv = strtol(argv[i], &p, 10);

// Check for errors: e.g., the string does not represent an integer
// or the integer is larger than int
  if (errno != 0 || *p != '\0' || conv > INT_MAX)
    {
      printf("this is word:%s\n ",p);
      //printf("chyba");
    }
  else
    {
    // No error
    num = conv;
    printf("this is number: %d\n", num);
  }

    i = i + 1;

  }
  return 0;
}

Answer 1

No, because strol() and the like convert the initial substring that matches. If you were to call it again on the rest of the string, though, you would need to strip out the dashes, or they would be interpreted as minus signs.

Answer 2

The reason it appears that strtol() did not convert the text 2015 is because you want the terminating character to be '\\0' in this line

if (errno != 0 || *p != '\0' || conv > INT_MAX)

But the text 2015 in 2015-08-26 is terminated by the '-' character.

So I recommend changing the line to

if (errno != 0 || (*p != '\0' && *p != '-') || conv > INT_MAX)

There are other ways to tackle it: your code won't break the date into its parts. You can do that by using strtok() but that wasn't your question.