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构建课程时遇到问题。类“Graph”在另一个文件中导入一个类“Bag”,并使用“Bag”作为其组件。如何在另一个C++头文件中导入一个类?
//Graph.h
#ifndef GRAPH_H
#define GRAPH_H
#include <fstream>
#include <iostream>
#include <vector>
#include "Bag.h"
class Bag;
class Graph
{
public:
Graph(int V);
Graph(std::ifstream& in_file);
int getV() { return V; }
int getE() { return E; }
void addEdge(int v, int w);
void showadj() ;
private:
int V;
int E;
std::vector<Bag> adj;
};
#endif
而 “Bag.h” 是如下:
//Bag.h
#ifndef BAG_H
#define BAG_H
#include <vector>
#include <iostream>
class Bag
{
public:
Bag();
void addBag(int i) { content.push_back(i); }
void showBag();
private:
std::vector<int> content;
};
#endif
Graph.cpp:
//Graph.cpp
#include "Graph.h"
#include "Bag.h"
Graph::Graph(int V) : V(V), E(0)
{
for (int i = 0; i < V; i++)
{
Bag bag;
adj.push_back(bag);
}
}
Bag.cpp(对不起,忘了):
#include "Bag.h"
void Bag::showBag()
{
for (int i : content)
{
std::cout << i << " ";
}
}
当我尝试编译这两个类时,出现一个错误:
C:\Users\ADMINI~1\AppData\Local\Temp\ccMj4Ybn.o:newtest.cpp:(.text+0x1a2): undef
ined reference to `Bag::Bag()'
collect2.exe: error: ld returned 1 exit status
你需要建立'Bag.cpp'成'Bag.o'与'Graph.o' – StoryTeller
袋联系起来。 cpp好奇地从这个问题中遗漏。 –
如果您从'Graph.h'中删除'class Bag;'并从'Graph.cpp'中删除'#include“Bag.h”',它会起作用(因为'Graph.h'已经包含'Bag.h' )? – Aemyl