In C, you would use strchr from string.h to do that.

Simple implementation

char* strchr(const char* str, int ch)
{
    while(*str && *str != (char)ch) str++;
    return (*str == (char)ch ? str : NULL);
}

I don't know why it takes an int rather than a char as second argument ;)

Using char[3] for num1 and num2 is not good, you need to leave room for the '\0' terminator if you are going to use it as a null terminated string later on, so make them char[4] instead. EDIT: And readLine nees to be char[8] as well.

EDIT: Whoops, used str instead of ch in the return statement there, fixed now.

Yep, that's probably the best plan although since he is only looking for a single delimiter character it's easy to roll your own version using strchr. Looks a bit like homework so I didn't go into too much detail.

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

int divideAndRefer(char* base, char** num1, char** num2){
    char* delimiter = strchr(base, ':');
    if (delimiter != NULL){
        *delimiter = '\0';
        *num1 = base;
        *num2 = delimiter + 1;
        return 1;
    }
    return 0;
}

int divideAndCopy(char* base, char* num1, int sizeNum1, char* num2, int sizeNum2){
    char* delimiter = strchr(base, ':');
    if (delimiter != NULL){
        char former = *delimiter;
        *delimiter = '\0';
        snprintf(num1, sizeNum1, "%s", base);
        snprintf(num2, sizeNum2, "%s", delimiter+1);
        *delimiter = former;
        return 1;
    }
    return 0;
}

int main(void){

    char readLine[8] = "001:330";
    char* num1, *num2;

    divideAndRefer(readLine, &num1, &num2);

    printf("%s %s.\n", num1, num2);

    char readLine2[8] = "001:330";
    char num3[4], num4[4];

    divideAndCopy(readLine2, num3, sizeof(num3), num4, sizeof(num4));

    printf("%s %s %s.\n", readLine2, num3, num4);

    return 0;

}

First thing, you need 8 bytes to keep the string "001:330", since you need an extra for the '\0'.

I am not a fan of strtok, so here you have two functions that will do what you need. The first one will change the content of the readline, so you won't be able to use it anymore, but it is faster and uses less memory. The second will copy the content to other variables. You should probably study both of them and understand how they work, feel free to ask any part you don't understand.

Good luck.

Ewww I don't like strtok any more ;) It needs to allocate per thread local storage to be thread safe, and that (avoiding a race condition) seems to be optional from the documentation?

The point where the last token was found is kept internally by the function to be used on the next call (particular library implementations are not required to avoid data races).

Yikes-a-mundo