Question

我的C ++代码有问题。如果我在#include "god.hpp"中插入neuron.hpp，g++会向我显示以下错误：

In file included from neuron.hpp:4,
             from main.cpp:5:
god.hpp:11: error: ‘Neuron’ has not been declared
god.hpp:13: error: ‘Neuron’ was not declared in this scope
god.hpp:13: error: template argument 1 is invalid
god.hpp:13: error: template argument 2 is invalid
main.cpp: In function ‘int main()’:
main.cpp:36: error: no matching function for call to ‘God::regNeuron(Neuron*&)’
god.hpp:11: note: candidates are: long int God::regNeuron(int*)
In file included from god.hpp:5,
             from god.cpp:3:
neuron.hpp:10: error: ‘God’ has not been declared
In file included from neuron.hpp:4,
             from neuron.cpp:2:
god.hpp:11: error: ‘Neuron’ has not been declared
god.hpp:13: error: ‘Neuron’ was not declared in this scope
god.hpp:13: error: template argument 1 is invalid
god.hpp:13: error: template argument 2 is invalid

以下是必要文件的相关（部分）：

//main.cpp
#include <string>
#include <vector>
#include "functions.hpp"
#include "neuron.hpp"
#include "god.hpp"
using namespace std;

int main()
{
God * god = new God();

vector<string>::iterator it;
for(it = patterns.begin(); it != patterns.end(); ++it) {
    Neuron * n = new Neuron();
            god->regNeuron(n);
    delete n;
    cout << *it << "\n";
}
}

上帝;）谁将处理所有神经元...

//god.hpp
#ifndef GOD_HPP
#define GOD_HPP 1 

#include <vector>
#include "neuron.hpp"

class God
{
public:
    God();
    long regNeuron(Neuron * n);
private:
    std::vector<Neuron*> neurons;
};
#endif

//god.cpp
#include <iostream>
#include <vector>
#include "god.hpp"
#include "neuron.hpp"

using namespace std;


God::God()
{
vector<Neuron*> neurons;
}

long God::regNeuron(Neuron * n)
{
neurons.push_back(n);
cout << neurons.size() << "\n";
return neurons.size();
}

至少，我的神经元。

//neuron.hpp
#ifndef NEURON_HPP
#define NEURON_HPP 1

#include "god.hpp" //Evil

class Neuron
{
public:
    Neuron();
    void setGod(God *g);
};
#endif

//neuron.cpp
#include <iostream>
#include "neuron.hpp"

#include "god.hpp"

Neuron::Neuron()
{
}

void Neuron::setGod(God *g)
{
std::cout << "Created Neuron!";
}

我希望有人能帮助我找到错误。当我在#include "god.hpp"中写neuron.hpp时会发生这种情况。我用Google搜索了大约三个小时，但我没有运气。

亲切的问候 -Boris

编译：

g++ -Wall -o getneurons main.cpp functions.cpp god.cpp neuron.cpp

Answer 1

删除

#include "god.hpp"

并将其替换为前向声明：

//neuron.hpp
#ifndef NEURON_HPP
#define NEURON_HPP 1

class God;  //forward declaration

class Neuron
{
public:
    Neuron();
    void setGod(God *g);
};
#endif

God.hpp相同：

//god.hpp
#ifndef GOD_HPP
#define GOD_HPP 1 

#include <vector>

class Neuron; //forward declaration

class God
{
public:
    God();
    long regNeuron(Neuron * n);
private:
    std::vector<Neuron*> neurons;
};
#endif

请注意，您需要在实施文件中包含。（cpp个文件）

如果使用指针或对象的引用作为成员或将该类型用作返回类型或参数，则不需要完整定义，因此前向声明就足够了。

G ++错误：在包含的文件中，未声明Foo

1 个答案: