重載模板操作符

Question

我想重載我的模板Vector類的+ =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; 
    }; 

}; 

完成投入過載爲+ = opperator我得到很多下列錯誤：

錯誤C2805：二進制 '操作符+ =' 太少參數

錯誤C4430：缺少類型說明符 - 假定爲int。注意：C++不支持default-int

錯誤C2334：在'{'之前的意外標記（s）跳過明顯的功能體。

錯誤C2238：在';'之前的意外標記（s）

語法錯誤：缺少';' '<'

錯誤C2143：語法錯誤：缺少';' '++'之前

錯誤C2143：語法錯誤：在'之前'缺少''''''

錯誤C2059：語法錯誤： '迴歸'

錯誤C2059：語法錯誤： '對'

錯誤C2059：語法錯誤： '）'

的，爲什麼解釋或者這些錯誤如何實際上由我做錯的事情引起的可能是有用的。謝謝

Answer 1

我能夠通過從+ =運算符定義之前刪除friend關鍵字來阻止錯誤。根據這一頁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 
    } 
}; 

這是+和+ = opperators應該如何超載。