C++ 警告：条件的第二个/第三个操作数无效[-Wunused value]

怎么了？

您的代码转换为：

second operand of conditional expression has no effect [-Wunused-value]
third operand of conditional expression has no effect [-Wunused-value]

或

我的意思是

std:：cout
second operand of conditional expression has no effect [-Wunused-value]
third operand of conditional expression has no effect [-Wunused-value]

((std::cout << (abs(b - c) < a)) && a < b + c) ? 1 : 0;

std::cout << (abs(b - c) < a && a < b + c ? 1 : 0);
// same as std::cout << ((abs(b - c) < a && a < b + c) ? 1 : 0);

std::cout << (abs(b - c) < a && (a < b + c ? 1 : 0));

std::cout << (abs(b - c) < a && a < b + c);