在C中，是否保证1/2 == 0？ [英] In C, is it guaranteed that 1/2 == 0?

问题描述

在C中保证 1/2 == 0 ？我需要它来实现二进制搜索：

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;
        }
    }
}

推荐答案

是的，这是有保证的。根据C ISO规范，§ 6.5.5 / 5：

Yes, this is guaranteed. According to the C ISO spec, §6.5.5/5:

/运算符的结果是来自分区的商
秒的第一个操作数;

The result of the / operator is the quotient from the division of the first operand by the second;

1/2的商为0，所以在C中保证1/2 <= 0 为真。

The quotient of 1 / 2 is 0, so 1 / 2 == 0 is guaranteed to be true in C.

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