How to split string in C without using strtok

Question

#include <stdio.h>
int
main() {
    char string[] = "my name is geany";
    int length = sizeof(string)/sizeof(char);
    printf("%i", length);
    int i;
    for ( i = 0; i<length; i++ ) {

    }   
    return 0;
}

if i want to print "my" "name" "is" and "geany" separate then what do I do. I was thinking to use a delimnator but i dont know how to do it in C

Solution 1

1. start with a pointer to the begining of the string
2. iterate character by character, looking for your delimiter
3. each time you find one, you have a string from the last position of the length in difference - do what you want with that
4. set the new start position to the delimiter + 1, and the go to step 2.

Do all these while there are characters remaining in the string...

Solution 2

I needed to do this because the environment was working in had a restricted library that lacked strtok. Here's how I broke up a hyphen-delimited string:

     b = grub_strchr(a,'-');
     if (!b)
       <handle error>
     else
       *b++ = 0;

     c = grub_strchr(b,'-');
     if (!c)
       <handle error>
     else
       *c++ = 0;

Here, a begins life as the compound string "A-B-C", after the code executes, there are three null-terminated strings, a, b, and c which have the values "A", "B" and "C". The <handle error> is a place-holder for code to react to missing delimiters.

Note that, like strtok, the original string is modified by replacing the delimiters with NULLs.

Solution 3

This breaks a string at newlines and trims whitespace for the reported strings. It does not modify the string like strtok does, which means this can be used on a const char* of unknown origin while strtok cannot. The difference is begin/end are pointers to the original string chars, so aren't null terminated strings like strtok gives. Of course this uses a static local so isn't thread safe.

#include <stdio.h> // for printf
#include <stdbool.h> // for bool
#include <ctype.h> // for isspace

static bool readLine (const char* data, const char** beginPtr, const char** endPtr) {
    static const char* nextStart;
    if (data) {
        nextStart = data;
        return true;
    }
    if (*nextStart == '\0') return false;
    *beginPtr = nextStart;

    // Find next delimiter.
    do {
        nextStart++;
    } while (*nextStart != '\0' && *nextStart != '\n');

    // Trim whitespace.
    *endPtr = nextStart - 1;
    while (isspace(**beginPtr) && *beginPtr < *endPtr)
        (*beginPtr)++;
    while (isspace(**endPtr) && *endPtr >= *beginPtr)
        (*endPtr)--;
    (*endPtr)++;

    return true;
}

int main (void) {
    const char* data = "  meow ! \n \r\t \n\n  meow ?  ";
    const char* begin;
    const char* end;
    readLine(data, 0, 0);
    while (readLine(0, &begin, &end)) {
        printf("'%.*s'\n", end - begin, begin);
    }
    return 0;
}

Output:

'meow !'
''
''
'meow ?'