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Splitting by the string "malloc" isn't working and returns a different split

March 8, 2022

char str[2500] ="int *x = malloc(sizeof(int));";
    const char s[9] = "malloc";
    char *token = strtok(str, s);

    while( token != NULL ) {
      printf("%s\n", token );
    
      token = strtok(NULL, s);
    }

Output:

int *x = 
(size
f(int));

I want it to return:

int *x = 
(sizeof(int));

but oddly it refuses to do that and I can’t seem to figure out why it’s doing that.

edit: I realized that the size is too small, but still has a problem.

>Solution :

The second parameter of the function strtok means that any character present in the string can be used as a terminating character.

So this substring

(sizeof(int))

is terminated as soon as the character ‘o’ present in the string "malloc" is found.

What you need to use is the standard C string function strstr. It will find the sub-string "mallpc" in the source string and you will be able to output the sub-strings before "malloc" and after it.

For example

char str[2500] ="int *x = malloc(sizeof(int));";
    const char s[9] = "malloc";
    char *p = strstr(str, s);

    if ( p != NULL )
    {
        printf( "%.*s\n", ( int )( p - str ), str );
        if ( p[strlen( s )] != '\0' ) puts( p );
    }