Are assignments in the condition part of conditionals a bad practice

coding-styleprogramming practices

Let's assume I want to write a function that concatenates two strings in C.
The way I would write it is:

void concat(char s[], char t[]){
    int i = 0;
    int j = 0;

    while (s[i] != '\0'){
        i++;
    }

    while (t[j] != '\0'){
        s[i] = t[j];
        i++;
        j++;
    }

    s[i] = '\0';

}

However, K&R in their book implemented it differently, particularly including as much in the condition part of the while loop as possible:

void concat(char s[], char t[]){
    int i, j;
    i = j = 0;
    while (s[i] != '\0') i++;

    while ((s[i++]=t[j++]) != '\0');

}

Which way is preferred? Is it encouraged or discouraged to write code the way K&R do? I believe my version would be easier to read by other people.

Best Answer

Always prefer clarity over cleverness. In yesteryears the best programmer was that whose code nobody could understand. "I cannot make sense of his code, he must be a genius", they said. Nowadays the best programmer is that whose code anyone can understand. Computer time is cheaper now than programmer's time.

Any fool can write code that a computer can understand. Good programmers write code that humans can understand. (M. Fowler)

So, no doubt, I'd go for option A. And that is my definitive answer.

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