问题
Is it guaranteed in C that 1/2 == 0? I need that for an implementation of binary search:
/*
* len is the array length
* ary is an array of ptrs
* f is a compare function
* found is a ptr to the found element in the array
* both i and offset are unsigned integers, used as indexes
*/
for(i = len/2; !found && i < len; i += offset) {
res = f(c->ary[i]);
if (res == 0) {
found = c->ary[i];
}
else {
offset = (res < 0 ? -1 : 1) * (i/2);
if (!offset) {
i = len+1;
}
}
}
回答1:
Yes, this is guaranteed. According to the C ISO spec, §6.5.5/5:
The result of the / operator is the quotient from the division of the first operand by the second;
The quotient of 1 / 2 is 0, so 1 / 2 == 0 is guaranteed to be true in C.
Hope this helps!
来源：https://stackoverflow.com/questions/19598608/in-c-is-it-guaranteed-that-1-2-0