Split string with delimiters in C

Question

How do I write a function to split and return an array for a string with delimiters in the C programming language?

char* str = \"JAN,FEB,MAR,APR,MAY,JUN,JUL,         


        

Answer 1

In the above example, there would be a way to return an array of null terminated strings (like you want) in place in the string. It would not make it possible to pass a literal string though, as it would have to be modified by the function:

#include 
#include 
#include 

char** str_split( char* str, char delim, int* numSplits )
{
    char** ret;
    int retLen;
    char* c;

    if ( ( str == NULL ) ||
        ( delim == '\0' ) )
    {
        /* Either of those will cause problems */
        ret = NULL;
        retLen = -1;
    }
    else
    {
        retLen = 0;
        c = str;

        /* Pre-calculate number of elements */
        do
        {
            if ( *c == delim )
            {
                retLen++;
            }

            c++;
        } while ( *c != '\0' );

        ret = malloc( ( retLen + 1 ) * sizeof( *ret ) );
        ret[retLen] = NULL;

        c = str;
        retLen = 1;
        ret[0] = str;

        do
        {
            if ( *c == delim )
            {
                ret[retLen++] = &c[1];
                *c = '\0';
            }

            c++;
        } while ( *c != '\0' );
    }

    if ( numSplits != NULL )
    {
        *numSplits = retLen;
    }

    return ret;
}

int main( int argc, char* argv[] )
{
    const char* str = "JAN,FEB,MAR,APR,MAY,JUN,JUL,AUG,SEP,OCT,NOV,DEC";

    char* strCpy;
    char** split;
    int num;
    int i;

    strCpy = malloc( strlen( str ) * sizeof( *strCpy ) );
    strcpy( strCpy, str );

    split = str_split( strCpy, ',', &num );

    if ( split == NULL )
    {
        puts( "str_split returned NULL" );
    }
    else
    {
        printf( "%i Results: \n", num );

        for ( i = 0; i < num; i++ )
        {
            puts( split[i] );
        }
    }

    free( split );
    free( strCpy );

    return 0;
}

There is probably a neater way to do it, but you get the idea.