3 ms·

It’s not wrong, just not as short as it can be. Comparing things that aren’t booleans with zero explicitly is a common style choice.

imglorp 7y ago
Well, the article is about the historical context of the idiom, and they got the context wrong. The full context (K&R second edition at least) is working through pointers and trimming down strcpy(). The '\0' one is version 2, and the following is version 3. As the final abbreviation, observe that a comparison against '\0' is redundant, since the question is merely whether the expression is zero. So the function would likely be written as /* strcpy: copy t to s; pointer version 3 */ void strcpy(char *s, char *t) { while (*s++ = *t++) ; } Although this may seem cryptic at first sight, the notational convenience is considerable, and the idiom should be mastered, because you will see it frequently in C programs. https://rkvalley.files.wordpress.com/2010/04/kernighan_ritchie_language_c.pdf https://rkvalley.files.wordpress.com/2010/04/kernighan_ritch... page 88
- rstuart4133 7y ago
  > the notational convenience is considerable, You are right of course - but this is a moment in time thing. ++ and it's equivalents aren't so convenient now. One of the things that strikes me about modern languages is the disappearance of integers, and the associated integer arithmetic such as the s++ in this example. It turns out we were using integers as a poor mans iterator, and s++ simply meant "next item please". Once we starting using "for element in sequence" to access iterators many of the integers disappeared - they are only used to represent integer things in the real world now. Just about every instance of ++ also disappeared because "next item in iterator" was it's main use. Turns out integers modelling things in the real world rarely need incrementing. So much so that modern languages don't bother including ++ or the Pascal equivalent, succ().

imglorp 7y ago

Well, the article is about the historical context of the idiom, and they got the context wrong. The full context (K&R second edition at least) is working through pointers and trimming down strcpy(). The '\0' one is version 2, and the following is version 3. As the final abbreviation, observe that a comparison against '\0' is redundant, since the question is merely whether the expression is zero. So the function would likely be written as /* strcpy: copy t to s; pointer version 3 */ void strcpy(char *s, char *t) { while (*s++ = *t++) ; } Although this may seem cryptic at first sight, the notational convenience is considerable, and the idiom should be mastered, because you will see it frequently in C programs. https://rkvalley.files.wordpress.com/2010/04/kernighan_ritchie_language_c.pdf https://rkvalley.files.wordpress.com/2010/04/kernighan_ritch... page 88

rstuart4133 7y ago
> the notational convenience is considerable, You are right of course - but this is a moment in time thing. ++ and it's equivalents aren't so convenient now. One of the things that strikes me about modern languages is the disappearance of integers, and the associated integer arithmetic such as the s++ in this example. It turns out we were using integers as a poor mans iterator, and s++ simply meant "next item please". Once we starting using "for element in sequence" to access iterators many of the integers disappeared - they are only used to represent integer things in the real world now. Just about every instance of ++ also disappeared because "next item in iterator" was it's main use. Turns out integers modelling things in the real world rarely need incrementing. So much so that modern languages don't bother including ++ or the Pascal equivalent, succ().