CODEWITHSUNDEEP
c++operator-overloadingoperator-keywordoperator-precedence
Rollmops
Rollmops

Reputation: 392

Catenate different operators

I am trying to implement a class that supports concatenation with different operators:

class MyClass {
public:

template<typename T>
MyClass &operator<<(const T& val ) {
  //do something with val
  return *this;
}

template<typename T>
MyClass &operator=(const T& val) {
  //do something with val
  return *this;
} 

};

int main() {
  MyClass a;
  a << "hallo" = 3 << "huuh"; //compiler will complain about 
}

Do i miss something here?

Thanks a lot for your help!

Upvotes: 1

Views: 54

Answers (1)

user657267
user657267

Reputation: 21038

Due to operator precedence, the expression

a << "hallo" = 3 << "huuh";

is evaluated as

(a << "hallo") = (3 << "huuh");

and your compiler is complaining about the lack of a valid operator<<(int, const char[5]).

You will need to use brackets to change the precedence:

(a << "hallo" = 3) << "huuh";

That said, it is extremely hard to understand what is going on here, operators should be used to make things clearer, not harder to read.

Upvotes: 4

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