c++ - 类型 ‘double’ snd const char [3]' 到二进制 'operator<<' 的无效操作数

Question

这是我在尝试构建时收到的错误消息:

invalid operands of types ‘double’ snd const char [3]’ to binary 'operator<<'

显然我对此很陌生。任何帮助，将不胜感激。

代码如下:

 #include <iostream>
 using namespace std;


 int main () 
 {
     double x = 3;
     double y = 4;

     cout << "(" << x = y++ << ", " << y << ")" << endl;
     cout << "(" << x = ++y << ", " << y << ")" << endl;
     cout << "(" << x = y-- << ", " << y << ")" << endl;
     cout << "(" << x = --y << ", " << y << ")" << endl;

         return 0;
 }

Answer 1

=优先级低于 << ，将其更改为:

std::cout << "(" << (x = y++) << ", " << y << ")" << std::endl;
//                  ^       ^

参见 C++ Operator Precedence .