Saving a string until a last delimiter is found - C

Question

Is it possible to use strtok or some other string function to cut the string until the point where last delimiter is found.

Specific example would be date; I would like to transform "4.1.2017." to "4.1.2017" - without the dot at the end.

Answer 1

If you have a single delimiter, use strrchr to find its last occurrence in the string:

char str[] = "quick.brown.fox";
char *ptr = strrchr(str, '.');
if (ptr) {
    *ptr = '\0';
}
printf("%s\n"' str);

This produces the following output:

quick.brown

Answer 2

Like I explained in My comment (if you don't want to use strrchr or you cannot for some reasons) I'll create a Function which checks the position of that delimiter like this:

int my_strrchr(const char *ptr, const char delimiter){
    if (ptr == NULL ){
        printf("Error, NULL Pointer\n");
        return -1;
    }

    if ( *ptr == '\0' ){
        printf("Error, the Buffer is Empty\n");
        return 0;
    }

    int i = 0;
    int ret = 0;

    while( ptr[i] != '\0' ){
        if ( ptr[i] == delimiter ){
            ret = i;
        }
        i++;
    }

    return ret;
}

And use it Like this:

#include <stdio.h>

int main(void){
    char arr[] = "4.1.2017.";
    char delimiter = '.';

    int len;

    if( (len = my_strrchr(arr, delimiter)) > 0){
        while ( arr[len] != '\0'){
            arr[len] = '\0';
        }
        printf("%s\n", arr);
    }
}

See DEMO. Any way this is only to get you an Idea and as you can see I use no standard Functions here.