How can I separate a String into separate items (separated by space) with C

Question

Sorry I'm not sure how to correctly word the problem I'm having. I'm taking the user's input which is unsigned char, let's say unsigned char array = "123 343 342 4235 87 34 398" and now I would like to have each number in that String divided by the space into a separate array

items[0] = 123 items[1] = 343 items[2] = 342

and so forth. How can I approach this?

I forgot to mention I'm compiling with Linux so tutorialspoint.com/c_standard_library/c_function_strtok.htm

Does not compile for me or work

strtok() http://www.tutorialspoint.com/c_standard_library/c_function_strtok.htm — Eric J., Oct 09 '14 at 21:47
This question is asked very frequently. Did you already search SO for it? — 5gon12eder, Oct 09 '14 at 21:55

score 0 · Answer 1 · edited May 23 '17 at 12:16

this is indeed a common question, for example here: Tokenizing strings in C

but anyways, here is one answer:

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

int main(void) {
    const int maxParsed = 32;
    char array[] = "123 343 342 4235 87 34 398";

    char* parsed[maxParsed];
    char* token = strtok(array, " ");

    int numParsed = 0;
    int i;

    while(token) {
        parsed[numParsed] = token;
        token = strtok(NULL, " ");
        numParsed++;
        if(numParsed == maxParsed) { break; }
    }


    for(i=0; i<numParsed; i++) {
        printf("parsed string %d: %s \n", i, parsed[i]);
    }
}

EDIT: This code fails in the edge case where the input is non-empty and contains no delimiters. You should check for that condition if the first call to strtok() returns NULL.

The edge case here is if the input only has one set of numbers with no space. Then your first `strtok` will return NULL and you won't have parsed anything. — Cameron Bielstein, Oct 09 '14 at 22:57

score -1 · Answer 2 · answered Oct 09 '14 at 21:59

You want to use strtok in combinaison with atoi for retrieving integers

I adapted the library example from tutorialpoints.

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

int main()
{
   const char str[27] = "123 343 342 4235 87 34 398";
   const char s[2] = " "; //Your delimiter, here a singlespace
   char *token;

  /* get the first token */
  token = strtok(str, s);

  /* walk through other tokens */
  while( token != NULL ) 
  {
      printf( " %d\n", atoi(token) ); // atoi converting char* to int !

      token = strtok(NULL, s);
  }

  return 0;
}

Downvoter : Please explain why you did not find this answer suitable. — Mekap, Apr 22 '15 at 14:19

How can I separate a String into separate items (separated by space) with C

2 Answers2