c - 鉴于此代码片段，输出是否依赖于 CPU？

Question

void main() {

        if(-1 > 0U)
                printf("True\n");
        else
                printf("False\n");
}

它是否依赖于处理器(大端/小端)？

Answer 1

来自 C99 6.3.1.8 :

[...] Otherwise, if the operand that has unsigned integer type has rank greater or equal to the rank of the type of the other operand, then the operand with signed integer type is converted to the type of the operand with unsigned integer type.

因为 int 和 unsigned int 具有相同的转换等级(参见 6.3.1.1 )，-1 将被转换为 unsigned int。根据 6.3.1.3 , 转换结果将是 (-1 + UINT_MAX + 1) % (UINT_MAX + 1) (算术上)这显然是 UINT_MAX 因此大于 0 。

结论是 C 标准要求 (-1 > 0U) 为真。