Question

我正在关注YouTube tutorial to build an FPS game in C++，但我遇到了一个我无法解决的错误;链接器错误LNK2019：

错误1错误LNK2019：未解析的外部符号“public：__thiscall Vector3d :: ~Vector3d（void）”（?? 1Vector3d @@ QAE @ XZ）在函数“class std :: basic_ostream＆gt;＆amp; __cdecl operator＆lt; ＆lt;（class std :: basic_ostream＆gt;＆amp;，class Vector3d）“（?? 6 @ YAAAV？$ basic_ostream @ DU？$ char_traits @ D @ std @@@ std @@ AAV01 @ VVector3d @@@ Z）<登记/> c：\ Users \ daniel \ documents \ visual studio 2012 \ Projects \ Project2 \ Project2 \ Vector3d.obj Project2

我需要做些什么来解决这个问题？

这是Vector3d中声明的Vector3d.h类：

#ifndef VEC_H
#define VEC_H

#include<iostream>
#include<cmath>

class Vector3d
{
  public:
    float x,y,z;
    Vector3d(void);
    Vector3d(float,float);
    Vector3d(float,float,float);
    ~Vector3d(void);

    float dotPrudect(const Vector3d& vec2);
    Vector3d crossproduct(const Vector3d& vec2);

    float lenght();
    void normalize();

    void change(float a,float b,float c);
    void change(Vector3d& vec2);
    void change(Vector3d vec2);
    void changeX(float a);
    void changeY(float b);
    void changeZ(float c);

    Vector3d operator+(const Vector3d& vec2);
    Vector3d operator-(const Vector3d& vec2);
    Vector3d operator*(const float& num);
    Vector3d operator/(const float& num);
    Vector3d& operator+=(const Vector3d& vec2);
    Vector3d& operator-=(const Vector3d& vec2);
    Vector3d& operator*=(const float& num);
    Vector3d& operator/=(const float& num);
    bool operator==(const Vector3d& vec2);
    bool operator!=(const Vector3d& vec2);
    friend std::ostream& operator<<(std::ostream& out,Vector3d vec2);
};

#endif

相应的Vector3d.cpp实施：

#include "Vector3d.h"

Vector3d::Vector3d()
{
    x=y=z=0;
}

Vector3d::Vector3d(float a,float b)
{
    x=a;
    y=b;
    z=0;
}

Vector3d::Vector3d(float a,float b,float c)
{
    x=a;
    y=b;
    z=c;
}

float Vector3d::dotPrudect(const Vector3d& vec2)
{
    return (x*vec2.x+y*vec2.y+z*vec2.z);
}

Vector3d Vector3d::crossproduct(const Vector3d& vec2)
{
    return (Vector3d(y*vec2.z-z*vec2.y,x*vec2.z-z*vec2.x,x*vec2.y-y*vec2.x));
}

float Vector3d::lenght()
{
    return (sqrt(x*x+y*y+z*z));
}

void Vector3d::change(float a,float b,float c)
{
    x=a;
    y=b;
    z=c;
}

void Vector3d::change(Vector3d vec)
{
    x=vec.x;
    y=vec.y;
    z=vec.z;
}

void Vector3d::change(Vector3d& vec)
{
    x=vec.x;
    y=vec.y;
    z=vec.z;
}

void Vector3d::changeX(float a)
{
    x=a;
}

void Vector3d::changeY(float b)
{
    y=b;
}

void Vector3d::changeZ(float c)
{
    z=c;
}


void Vector3d::normalize()
{
    float len=lenght();
    if(len!=0)
    {
        x/=len;
        y/=len;
        z/=len;
    }
}

Vector3d Vector3d::operator+(const Vector3d& vec2)
{
    return (Vector3d(x+vec2.x,y+vec2.y,z+vec2.z));
}

Vector3d Vector3d::operator-(const Vector3d& vec2)
{
    return (Vector3d(x-vec2.x,y-vec2.y,z-vec2.z));
}

Vector3d Vector3d::operator*(const float& num)
{
    return (Vector3d(x*num,y*num,z*num));
}

Vector3d& Vector3d::operator+=(const Vector3d& vec2)
{
    x+=vec2.x;
    y+=vec2.y;
    z+=vec2.z;
    return *this;
}

Vector3d& Vector3d::operator-=(const Vector3d& vec2)
{
    x-=vec2.x;
    y-=vec2.y;
    z-=vec2.z;
    return *this;
}

Vector3d& Vector3d::operator*=(const float& num)
{
    x*=num;
    y*=num;
    z*=num;
    return *this;
}

Vector3d& Vector3d::operator/=(const float& num)
{
    if(num!=0)
    {
        x/=num;
        y/=num;
        z/=num;
    }
    return *this;
}

bool Vector3d::operator==(const Vector3d& vec2)
{
    return (x==vec2.x && y==vec2.y && z==vec2.z);
}

bool Vector3d::operator!=(const Vector3d& vec2)
{
    return (x!=vec2.x && y!=vec2.y && z!=vec2.z);
}

std::ostream& operator<<(std::ostream& out,Vector3d vec2)
{
    out << vec2.x << "\t" << vec2.y << "\t" << vec2.z << std::endl;
    return out;
}

Answer 1

您在头文件中声明了析构函数：

class Vector3d
{
  public:
    float x,y,z;
    Vector3d(void);
    Vector3d(float,float);
    Vector3d(float,float,float);
    ~Vector3d(void);
    ^^^^^^^^^^^^^^^^
    ...

但是你从未在任何地方实现它，你应该在Vector3d.cpp中添加一个实现：

Vector3d::~Vector3d()
{
   ...
}

如果您没有任何可销毁的东西，请删除Vector3d.h中的声明。

Answer 2

您的.h文件中声明了析构函数，但未在cpp中实现

~Vector3d(void); // you probably want to remove that line or default it if using C++11

声明一个空的析构函数首先是无用的，因为编译器无论如何都可以为你编写它，但更重要的是，因为C ++ 11它会阻止编译器生成一个移动构造函数，这将影响性能。

ERROR LINK 2019 c ++

2 个答案: