获取“错误LNK2019：未解析的外部符号”

时间：2013-02-11 11:13:24

标签： c++

这是我的代码。这是练习使用模板。

标题

#ifndef H_rectangleType
#define H_rectangleType

#include <iostream>

using namespace std;

namespace Rectangle{
template <class myType>
class rectangleType
{
      //Overload the stream insertion and extraction operators
    friend ostream& operator << (ostream&, const rectangleType &);
    friend istream& operator >> (istream&, rectangleType &);

public:
    void setDimension(myType l, myType w);
    myType getLength() const;
    myType getWidth() const;
    myType area() const;
    myType perimeter() const;
    void print() const;

    rectangleType<myType> operator+(const rectangleType<myType>&) const;
      //Overload the operator +
    rectangleType<myType> operator*(const rectangleType<myType>&) const;
      //Overload the operator *

        bool operator==(const myType&) const;
      //Overload the operator ==
    bool operator!=(const myType&) const;
      //Overload the operator !=

    rectangleType();
    rectangleType(myType l, myType w);

private:
    myType length;
    myType width;
};
}


#endif

会员定义

#include <iostream> 
#include "rectangleType.h"

using namespace std;

namespace Rectangle{
template <class myType>
void rectangleType<myType>::setDimension(myType l, myType w)
{
    if (l >= 0) 
        length = l;
    else
        length = 0;

    if (w >= 0)
        width = w;
    else
        width = 0;
}

template <class myType>
myType rectangleType<myType>::getLength() const
{
    return length;
}

template <class myType>
myType rectangleType<myType>::getWidth()const
{
    return width;
}

template <class myType>
myType rectangleType<myType>::area() const
{
    return length * width;
}

template <class myType>
myType rectangleType<myType>::perimeter() const
{
    return 2 * (length + width);
}

template <class myType>
void rectangleType<myType>::print() const
{
    cout << "Length = "  << length
         << "; Width = " << width;
}

template <class myType>
rectangleType<myType>::rectangleType(myType l, myType w)
{
    setDimension(l, w);
}    

template <class myType>
rectangleType<myType>::rectangleType()
{
    length = 0;
    width = 0;
}

template <class myType>
rectangleType<myType> rectangleType<myType>::operator+ 
                          (const rectangleType<myType>& rectangle) const
{
    rectangleType<myType> tempRect;

    tempRect.length = length + rectangle.length;
    tempRect.width = width + rectangle.width;

    return tempRect;
}

template <class myType>
rectangleType<myType> rectangleType<myType>::operator* 
                       (const rectangleType<myType>& rectangle) const
{
    rectangleType<myType> tempRect;

    tempRect.length = length * rectangle.length;
    tempRect.width = width * rectangle.width;

    return tempRect;
}

template <class myType>
bool rectangleType<myType>::operator== 
                      (const myType& rectangle) const
{
    return (length == rectangle.length &&
            width == rectangle.width);
}

template <class myType>
bool rectangleType<myType>::operator!= 
                       (const myType& rectangle) const
{
    return (length != rectangle.length ||
            width != rectangle.width);
}

template <class myType2>
ostream& operator << (ostream& osObject, 
                      const rectangleType<myType2>& rectangle)
{
    osObject << "Length = "  << rectangle.length 
             << "; Width = " << rectangle.width;

return osObject;
}

template <class myType2>
istream& operator >> (istream& isObject, 
                      rectangleType<myType2>& rectangle)
{
    isObject >> rectangle.length >> rectangle.width;

    return isObject;
}
}

主要

#include <iostream>                                   //Line 1

#include "rectangleType.h"                            //Line 2

using namespace std;                                  //Line 3
using namespace Rectangle;

int main()                                            //Line 4
{                                                     //Line 5
    cout << "Enter the type of your Rectangle.\n1. int\n2. double\n3. float";
        rectangleType<double> myRectangle(23, 45);                //Line 6
    int int1 = 1;
    int double1 = 2;
    int float1 = 3;
    int temp= 0;
    cin >> temp;                                                      //Line 7

    if(temp == int1)
    {   
    rectangleType<int> myRectangle(23, 45);   
    rectangleType<int> yourRectangle;
        cout << "Line 8: myRectangle: " << myRectangle 
     << endl;                                     

        cout << "Line 9: Enter the length and width "
             <<"of a rectangle: ";                        
        cin >> yourRectangle;                            
        cout << endl;                                    

        cout << "Line 12: yourRectangle: "
             << yourRectangle << endl;                    

        cout << "Line 13: myRectangle + yourRectangle: " 
                     << myRectangle + yourRectangle << endl;     
        cout << "Line 14: myRectangle * yourRectangle: " 
                 << myRectangle * yourRectangle << endl;
    } 

    if(temp == double1)
    {   
        rectangleType<double> myRectangle(23, 45);   
    rectangleType<double> yourRectangle;
    cout << "Line 8: myRectangle: " << myRectangle 
     << endl;                                     

    cout << "Line 9: Enter the length and width "
         <<"of a rectangle: ";                        
    cin >> yourRectangle;                            
    cout << endl;                                    

    cout << "Line 12: yourRectangle: "
         << yourRectangle << endl;                    

    cout << "Line 13: myRectangle + yourRectangle: " 
         << myRectangle + yourRectangle << endl;     
    cout << "Line 14: myRectangle * yourRectangle: " 
         << myRectangle * yourRectangle << endl;
} 

if(temp == float1)
{   
    rectangleType<float> myRectangle(23, 45);   
    rectangleType<float> yourRectangle;
    cout << "Line 8: myRectangle: " << myRectangle 
     << endl;                                     

    cout << "Line 9: Enter the length and width "
         <<"of a rectangle: ";                        
    cin >> yourRectangle;                            
    cout << endl;                                    

    cout << "Line 12: yourRectangle: "
         << yourRectangle << endl;                    

    cout << "Line 13: myRectangle + yourRectangle: " 
         << myRectangle + yourRectangle << endl;     
    cout << "Line 14: myRectangle * yourRectangle: " 
         << myRectangle * yourRectangle << endl;
} 
return 0;

}

在这里，我收到了这些错误

1>testOpOverLoadClass.obj : error LNK2019: unresolved external symbol "public: class                                   Rectangle::rectangleType<float> __thiscall Rectangle::rectangleType<float>::operator*(class Rectangle::rectangleType<float> const &)const " (??D?$rectangleType@M@Rectangle@@QBE?AV01@ABV01@@Z) referenced in function _main
1>testOpOverLoadClass.obj : error LNK2019: unresolved external symbol "public: class Rectangle::rectangleType<float> __thiscall Rectangle::rectangleType<float>::operator+(class Rectangle::rectangleType<float> const &)const " (??H?$rectangleType@M@Rectangle@@QBE?AV01@ABV01@@Z) referenced in function _main
1>testOpOverLoadClass.obj : error LNK2019: unresolved external symbol "class std::basic_istream<char,struct std::char_traits<char> > & __cdecl Rectangle::operator>>(class std::basic_istream<char,struct std::char_traits<char> > &,class Rectangle::rectangleType<float> &)" (??5Rectangle@@YAAAV?$basic_istream@DU?$char_traits@D@std@@@std@@AAV12@AAV?$rectangleType@M@0@@Z) referenced in function _main
1>testOpOverLoadClass.obj : error LNK2019: unresolved external symbol "class std::basic_ostream<char,struct std::char_traits<char> > & __cdecl Rectangle::operator<<(class std::basic_ostream<char,struct std::char_traits<char> > &,class Rectangle::rectangleType<float> const &)" (??6Rectangle@@YAAAV?$basic_ostream@DU?$char_traits@D@std@@@std@@AAV12@ABV?$rectangleType@M@0@@Z) referenced in function _main
1>testOpOverLoadClass.obj : error LNK2019: unresolved external symbol "public: __thiscall Rectangle::rectangleType<float>::rectangleType<float>(void)" (??0?$rectangleType@M@Rectangle@@QAE@XZ) referenced in function _main
1>testOpOverLoadClass.obj : error LNK2019: unresolved external symbol "public: __thiscall Rectangle::rectangleType<float>::rectangleType<float>(float,float)" (??0?$rectangleType@M@Rectangle@@QAE@MM@Z) referenced in function _main
1>testOpOverLoadClass.obj : error LNK2019: unresolved external symbol "public: class Rectangle::rectangleType<double> __thiscall Rectangle::rectangleType<double>::operator*(class Rectangle::rectangleType<double> const &)const " (??D?$rectangleType@N@Rectangle@@QBE?AV01@ABV01@@Z) referenced in function _main
1>testOpOverLoadClass.obj : error LNK2019: unresolved external symbol "public: class Rectangle::rectangleType<double> __thiscall Rectangle::rectangleType<double>::operator+(class Rectangle::rectangleType<double> const &)const " (??H?$rectangleType@N@Rectangle@@QBE?AV01@ABV01@@Z) referenced in function _main
1>testOpOverLoadClass.obj : error LNK2019: unresolved external symbol "class std::basic_istream<char,struct std::char_traits<char> > & __cdecl Rectangle::operator>>(class std::basic_istream<char,struct std::char_traits<char> > &,class Rectangle::rectangleType<double> &)" (??5Rectangle@@YAAAV?$basic_istream@DU?$char_traits@D@std@@@std@@AAV12@AAV?$rectangleType@N@0@@Z) referenced in function _main
1>testOpOverLoadClass.obj : error LNK2019: unresolved external symbol "class std::basic_ostream<char,struct std::char_traits<char> > & __cdecl Rectangle::operator<<(class std::basic_ostream<char,struct std::char_traits<char> > &,class Rectangle::rectangleType<double> const &)" (??6Rectangle@@YAAAV?$basic_ostream@DU?$char_traits@D@std@@@std@@AAV12@ABV?$rectangleType@N@0@@Z) referenced in function _main
1>testOpOverLoadClass.obj : error LNK2019: unresolved external symbol "public: __thiscall Rectangle::rectangleType<double>::rectangleType<double>(void)" (??0?$rectangleType@N@Rectangle@@QAE@XZ) referenced in function _main
1>testOpOverLoadClass.obj : error LNK2019: unresolved external symbol "public: class Rectangle::rectangleType<int> __thiscall Rectangle::rectangleType<int>::operator*(class Rectangle::rectangleType<int> const &)const " (??D?$rectangleType@H@Rectangle@@QBE?AV01@ABV01@@Z) referenced in function _main
1>testOpOverLoadClass.obj : error LNK2019: unresolved external symbol "public: class Rectangle::rectangleType<int> __thiscall Rectangle::rectangleType<int>::operator+(class Rectangle::rectangleType<int> const &)const " (??H?$rectangleType@H@Rectangle@@QBE?AV01@ABV01@@Z) referenced in function _main
1>testOpOverLoadClass.obj : error LNK2019: unresolved external symbol "class std::basic_istream<char,struct std::char_traits<char> > & __cdecl Rectangle::operator>>(class std::basic_istream<char,struct std::char_traits<char> > &,class Rectangle::rectangleType<int> &)" (??5Rectangle@@YAAAV?$basic_istream@DU?$char_traits@D@std@@@std@@AAV12@AAV?$rectangleType@H@0@@Z) referenced in function _main
1>testOpOverLoadClass.obj : error LNK2019: unresolved external symbol "class std::basic_ostream<char,struct std::char_traits<char> > & __cdecl Rectangle::operator<<(class std::basic_ostream<char,struct std::char_traits<char> > &,class Rectangle::rectangleType<int> const &)" (??6Rectangle@@YAAAV?$basic_ostream@DU?$char_traits@D@std@@@std@@AAV12@ABV?$rectangleType@H@0@@Z) referenced in function _main
1>testOpOverLoadClass.obj : error LNK2019: unresolved external symbol "public: __thiscall Rectangle::rectangleType<int>::rectangleType<int>(void)" (??0?$rectangleType@H@Rectangle@@QAE@XZ) referenced in function _main
1>testOpOverLoadClass.obj : error LNK2019: unresolved external symbol "public: __thiscall Rectangle::rectangleType<int>::rectangleType<int>(int,int)" (??0?$rectangleType@H@Rectangle@@QAE@HH@Z) referenced in function _main
1>testOpOverLoadClass.obj : error LNK2019: unresolved external symbol "public: __thiscall Rectangle::rectangleType<double>::rectangleType<double>(double,double)" (??0?$rectangleType@N@Rectangle@@QAE@NN@Z) referenced in function _main
1>C:\Users\jr\Documents\Visual Studio 2010\Projects\CMPE 126\Lab 2\Debug\Lab 2.exe : fatal error LNK1120: 18 unresolved externals

我似乎无法做出这些错误的含义。谢谢inadvance

2 个答案:

答案 0 :(得分：2)

您不能将模板化类的定义和实现分开。您还必须将函数放在头文件中。

答案 1 :(得分：1)

调用代码应该可以看到模板函数定义。

内联他们。

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