字段类型不完整

Field has incomplete type

本文关键字：类型 字段      更新时间：2023-10-16
template <class Type>
class Punct {
    
protected:
    
    Type _x; // (1)
    Type _y; // (1)
    
public:
    Punct(Type = 0, Type = 0); // (2)
    ~Punct();
    inline Type getX() const { return _x; }
    inline Type getY() const { return _y; }
  
    inline void setX(Type x) { _x = x; }
    inline void setY(Type y) { _y = y; }
    inline void moveBy(int x, int y) { _x = x; _y = y; }
friend std::istream &operator>>(std::istream&ins, Punct<Type>& A);
friend std::ostream &operator<<(std::ostream&outs, const Punct<Type>& A);
};

这些是我得到的错误:

(1) -字段有不完整类型' type '

(2) -没有可行的从int到type的转换(有些添加3)。(此处传递参数给形参)

你能告诉我我做错了什么吗?

这段代码适合我。g++ 4.7.2 on Kubuntu 12.04 .

顺便说一下，您是否将Punct类的所有实现都放在一个文件中，即头文件，或者您将它们分开到.h和.cpp中?

#include <iostream>
using namespace std;
template <class Type>
class Punct {
protected:
    Type _x; // (1)
    Type _y; // (1)
public:
    Punct(Type = 0, Type = 0) {}; // (2) <- empty function body added
    ~Punct() {}; // <- empty function body added
    inline Type getX() const { return _x; }
    inline Type getY() const { return _y; }
    inline void setX(Type x) { _x = x; }
    inline void setY(Type y) { _y = y; }
    inline void moveBy(int x, int y) { _x = x; _y = y; }
    template<class T> // <- added
    friend std::istream &operator>>(std::istream&ins, Punct<T>& A);
    template<class T> // <- added
    friend std::ostream &operator<<(std::ostream&outs, const Punct<Type>& A);
};
// bogus function added
template<class T>
istream &operator>> (istream &i, Punct<T> &a)
{
    return i;
}
// bogus function added
template<typename T>
ostream &operator<< (ostream &i, const Punct<T>& a)
{
    return i;
}
int main()
{
    Punct<int> a;
}
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