In the days of K&R
- ‘C’ was portable assembly code
- It was used by programmers that thought in assembly code
- The compiler did not do much optimization
- Most computers had “complex instruction sets”,
for example
while ((s[i++]=t[j++]) != '\0')would map to one instruction on most CPUs (I expect the Dec VAC)
There days
- Most people reading C code are not assembly code programmers
- C compilers do lots of optimization, hence the simpler to read code is likely to be translated into the same machine code.
(A note on always using braces – the 1st set of code takes up more space due to having some “unneeded” {}, in my experience these often prevent code that has been badly merged from compiler and allow errors with incorrect “;” placements to be detected by tools.)
However in the old days the 2nd version of the code would have read. (If I got it right!)
concat(char* s, char *t){
while (s++);
--s;
while (s++=t++);
}
