相关疑难解决方法(0)

我在为模板类定义一些运算符重载时遇到了一些问题.让我们以这个假设的类为例.

template <class T>
class MyClass {
  // ...
};

• 操作者+ =

  // In MyClass.h
  MyClass<T>& operator+=(const MyClass<T>& classObj);
  
  
  // In MyClass.cpp
  template <class T>
  MyClass<T>& MyClass<T>::operator+=(const MyClass<T>& classObj) {
    // ...
    return *this;
  }
  

  Run Code Online (Sandbox Code Playgroud)

  导致此编译器错误:

  no match for 'operator+=' in 'classObj2 += classObj1'
  

  Run Code Online (Sandbox Code Playgroud)

• 运营商<<

  // In MyClass.h
  friend std::ostream& operator<<(std::ostream& out, const MyClass<T>& classObj);
  
  
  // In MyClass.cpp
  template <class T>
  std::ostream& operator<<(std::ostream& out, const MyClass<T>& classObj) {
      // ...
      return out;
  }
  

  Run Code Online (Sandbox Code Playgroud)

  结果在此编译器警告:

  friend declaration 'std::ostream& operator<<(std::ostream&, const MyClass<T>&)' …

  Run Code Online (Sandbox Code Playgroud)