Question

It has been a while since I looked at C (still learning) and I just got back into the K&R book.

I just had a go to Exercise 5-3 (p107).

Write a pointer version of the function strcat that we showed in Chapter 2: strcat(s,t) copies the string t to the end of s.

I came up with this…

void strcat(char *s, char *t);

void strcat(char *s, char *t) {

    while (*s++ != '\0');
    s--;
    while (*t != '\0') {
        *s++ = *t++;
    }

    *--t = '\0';

}

int main() {
   char str[] = "Hey, hello";
   char str2[] = " are you?";

   strcat(str, str2);

   printf("%s\n", str);

   return 0;

}

It seems to work.

What I am wondering, is that the K&R book often writes exercises with as little lines as possible – I’d expect had they provided their own code sample for above, you’d get things like this…

void strcat(char *s, char *t) {

    while (*s++ != '\0');
    s--;
    while ((*s++ = *t++) != '\0');
    *--t = '\0';

}

To me, this is less readable (maybe this example isn’t as good, but I often look at their code and think if that was separated into a few lines, I’d understand it much better). The examples provided in the book seem to advocate this sort of assignment in the condition part of a loop, and in fact cramming as much code as possible per line.

Is the book right in trying to do as much possible where you can, even if readability suffers?

Is this just The C Way?

Answer 1

K&R explain the importance of idioms in the book. Yes, brevity of code is valued by C programmers, but it’s not deliberately terse to punish beginners. After some time reading and writing C you start to recognize patterns, so when you see them in someone else’s code you know what you’re looking at.

Go through the iterations of strcpy() given as an example in K&R — they explain their philosophy of brevity vs. clarity, and talk about idioms.