摘要： bool foo() { unsigned int a = 6; int b = -20; // If 'b' is 'long long'? return a + b < 6 ? true : false; } If 'int b = -20;', the result is false, because 'a + b' => (unsigned + int) => (unsigned + unsigned) in integral promotion. Thus result is unsigned(-14) 阅读全文