Question

Consider a char array like this:

43 234 32 32

I want the last value that is 32 in integer form.

The string size/length is not known. In the above example there are 4 numbers, but the size will vary.

How can this be done?

Answer 1

If there is no trailing whitespace on the line:

int last_int(const char *s)
{
    const char *ptr = strrchr(s, ' ');
    if (ptr == NULL) {
        ptr = s;
    } else {
        ptr++;
    }

    return atoi(ptr);
}

If there can be trailing whitespace, then you’ll need to do something like what ProdigySim suggested, but with more states, to walk backwards past the trailing whitespace (if any), then past the number, then call atoi(). No matter what you do, you’ll need to watch out for boundary conditions and edge cases and decide how you want to handle them.