重载模板操作符

Question

我想重载我的模板Vector类的+ =操作符。

template<unsigned int dimensions, typename TValue> 
class Vector 
{ 
private: 
    std::array<TValue, dimensions> m_values; 
public: 
    Vector(){ 
     for (int i = 0; i < dimensions; i++){ 
      m_values[i] = TValue(); 
     } 
    }; 
    Vector(std::array<TValue, dimensions> elements){ 
     for (int i = 0; i < dimensions; i++){ 
      m_values[i] = elements[i]; 
     } 
    }; 

    inline void set(VectorDimensions dimension, TValue value){ 
     m_values[dimension] = value; 
    }; 

    inline TValue get(VectorDimensions dimension) const{ 
     return m_values[dimension]; 
    }; 

    inline unsigned int getSize() const{ 
     return dimensions; 
    }; 

    const std::array<TValue, dimensions> getValues() const{ 
     return m_values; 
    }; 

    friend ostream& operator<<(ostream& os, const Vector<dimensions, TValue>& vt) { 
     array<TValue, dimensions> values = vt.getValues(); 
     os << '['; 
     for (unsigned int i = 0; i < vt.getSize(); i++){ 
      os << values[i] << values[i+1] ? ", " : ""; 
     } 
     os << ']'; 
     return os; 
    }; 

    friend Vector<dimensions, TValue>& operator+=(const Vector<dimensions, TValue>& vt) { 
     array<TValue, dimensions> values = vt.getValues(); 
     for (unsigned int i = 0; i < vt.getSize(); i++){ 
      m_values[i] += values[i]; 
     } 
     return *this; 
    }; 

}; 

完成投入过载为+ = opperator我得到很多下列错误：

错误C2805：二进制 '操作符+ =' 太少参数

错误C4430：缺少类型说明符 - 假定为int。注意：C++不支持default-int

错误C2334：在'{'之前的意外标记（s）跳过明显的功能体。

错误C2238：在';'之前的意外标记（s）

语法错误：缺少';' '<'

错误C2143：语法错误：缺少';' '++'之前

错误C2143：语法错误：在'之前'缺少''''''

错误C2059：语法错误： '回归'

错误C2059：语法错误： '对'

错误C2059：语法错误： '）'

的，为什么解释或者这些错误如何实际上由我做错的事情引起的可能是有用的。谢谢

Answer 1

我能够通过从+ =运算符定义之前删除friend关键字来阻止错误。根据这一页http://en.cppreference.com/w/cpp/language/operators

class X { 
public: 
    X& operator+=(const X& rhs) // compound assignment (does not need to be a member, 
    {       // but often is, to modify the private members) 
    /* addition of rhs to *this takes place here */ 
    return *this; // return the result by reference 
    } 

    // friends defined inside class body are inline and are hidden from non-ADL lookup 
    friend X operator+(X lhs,  // passing first arg by value helps optimize chained a+b+c 
        const X& rhs) // alternatively, both parameters may be const references. 
    { 
    return lhs += rhs; // reuse compound assignment and return the result by value 
    } 
}; 

这是+和+ = opperators应该如何超载。