Question

我试图从另一个文件中的BST类声明对象'bst'。我无法让它工作。到目前为止，这是我尝试编译文件时的错误消息。

$ make -f makefile.txt
g++ -Wall -W -Werror -pedantic -g -c BSTapp.cpp
BSTapp.cpp: In function `int main()':
BSTapp.cpp:9: error: `BST' undeclared (first use this function)
BSTapp.cpp:9: error: (Each undeclared identifier is reported only once for each function it appears in.)
BSTapp.cpp:9: error: expected `;' before "bst"
makefile.txt:5: recipe for target `BSTapp.o' failed
make: *** [BSTapp.o] Error 1

这些是以....开头的文件 BST.h

#ifndef BST_H_INCLUDED
#define BST_H_INCLUDED

#include <iostream>
#include <string>

using namespace std;

class BST
{
public:
    BST();
    ~BST();
    void insert(int key, string data);
    void find(int key);
    void remove(int key, string data);
    void print();
    friend class Node;
private:
    Node* m_root;

};

#endif // BST_H_INCLUDED

bst.cpp

#include "BST.h"

void BST::insert(int key, string data)
{

}

bstapp.cpp（主要）

#include "BSTapp.h"
#include <iostream>
#include <string>
#include <cstring>
#include <algorithm>
using namespace std;
int main()
{
    BST bst; //<<this is where I am trying to declare the object.
    cout << "hi" << endl;
    cout << "in main" << endl;
    string line;
    string command = "aaaa";
    string strKey;
    string data;
    //char ignore[] = "/";
    while(command != "quit")
    {
        cout << "in while loop" << endl;
        cin >> command;
        cout << "Command is:" << command << endl;
        if(command == "insert")
        {
            cin >> strKey;
            strKey.erase(2, 1);
            int intKey = atoi(strKey.c_str());
            cout << intKey << endl;
            cin.ignore();
            getline(cin, data);
            cout << data << endl;
        }
        if(command == "find")
        {

        }
        if(command == "delete")
        {

        }
        if(command == "print")
        {

        }
    }
    return 0;
}

BSTapp.h

#ifndef BSTAPP_H_INCLUDED
#define BSTAPP_H_INCLUDED

#include <string>
#include <iostream>

using namespace std;

/*class NodeData
{
public:
    NodeData(int key, string data)
    {m_key = key; m_data = data;}
    //~NodeData(); // add this in eventually
private:
    int m_key;
    string m_data;

};*/
class BSTapp
{
public:
private:
};

#endif // BSTAPP_H_INCLUDED

朋友节点被声明为......

    #ifndef NODE_H_INCLUDED
    #define NODE_H_INCLUDED

    #include <iostream>
    #include <string>

    using namespace std;
class Node
{
public:
    Node(int key, string data)
    {m_key = key; m_data = data;}
    ~Node();
    //friend BST();
private:
    int m_key;
    string m_data;
    Node *m_left;
    Node *m_right;
    //Node *m_parent;
};


#endif // NODE_H_INCLUDED

基本上，我只想在int main中声明一个对象，这样我就可以在BST中构造一个新的Node（赋值需要我使用所有这些文件，所以我不能把所有内容放到.h和.cpp中，它必须是6）。同样，我无法找到如何在main中声明一个对象。请告诉我，如果我遗漏了你需要的任何信息，我在这个网站上提问时我真的很难。

Answer 1

BSTapp是BST的用户，因此必须包含它。没有其他办法。

声明另一个文件中的对象

1 个答案: