对CLASS :: function（）的未定义引用(undefined reference to CLASS::function())

 因此，当我尝试使用“g ++ Asg5.cpp”简单地编译我的代码时，我收到以下错误 
 
 
 
 /tmp/cczhpSGO.o：在函数'main'中： 
 
 
 Asg5.cpp :(。text + 0x2fb）：对'BinomialTree :: insert（int）'的未定义引用 
 
 
 collect2：ld返回1退出状态 
 
 
 如果有人想知道我为什么不使用makefile，我的教授只想输入g ++ <。cpp with main（）>来编译.. 
 
 无论如何这里是我的代码我非常感谢你的帮助！ 
 
 Asg5.cpp 
 
#include "BinomialTree.h"
#include "BinomialNode.h"
#include <iostream>
#include <vector>
#include <fstream>
#include <sstream>
#include <stdlib.h>
#include <string>
#include <stdio.h>

using namespace std;
int main(int argc, char* argv[])
{
    //input handling
    if(argc != 2)
    {
        cout << "Incorrect Usage. \n Example: ./a.out <filename>" << endl;
        exit(1);
    }
    BinomialTree *tree = new BinomialTree(); 

    char *buffer;
    char *token;
    //read file into buffer.**************************************
    string input;
    ifstream file;
    file.open(argv[1]);
    if(file.is_open())
    {
        string str;
        while(file.good())
        {
            getline(file,str);
            input += " " + str;
        }
    }
    else{
        cout << "File not found"<< endl;
        return 1;
    }
    file.close();

    int buf;
    stringstream ss(input);

    vector<int> tokens;

    while(ss >> buf)
    {
        tokens.push_back(buf);
    }
    int i = 0;
    for(i = 0; i < tokens.size(); i++)
        tree->insert(tokens[i]);
    //end file reading *******************************************
    delete tree;
}
 
 BinomialNode.h 
 
#ifndef _BINOMIALNODE_H_
#define _BINOMIALNODE_H_
#include "BinomialTree.h"
class BinomialNode
{
    public: 
        int k;
        BinomialNode *children[20];
        int data;

        BinomialNode();
};
#endif
 
 BinomialNode.cpp 
 
class BinomialNode
{   
    BinomialNode::BinomialNode(int n)
    {   
        this->k = 0;
        this->data = n;
    }
}
 
 BinomialTree.h 
 
#ifndef _MULTIMAP_H_
#define _MULTIMAP_H_
#include "BinomialNode.h"

class BinomialTree
{
    public:
        BinomialNode * BQ[20];


        void insert(int n);
        void merge(BinomialNode *queue, BinomialNode *in, int k);
        void print(BinomialNode *root, int tab);
};
#endif
 
 BinomialTree.cpp 
 
#include "BinomialNode.h"
#include "BinomialTree.h"
#include <iostream>
#include <cstdlib>


class BinomialTree
{
    void BinomialTree::insert(int n)
    {
        BinomialNode *in = new BinomialNode(n);
        if(BQ[0] == NULL)
        {
            BQ[0] = in;
            return;
        }
        else
            merge(BQ[0], in, 0);
    }
    void BinomialTree::merge(BinomialNode *queue, BinomialNode *in, int k)
    {
        if(queue == NULL)
        {
            BQ[k] = in;
            return;
        }
        if(n == NULL)
        {
            BQ[k] = queue;
            return;
        }
        if(queue->data > in->data)
        {   
            merge(in, queue);
            return;
        }
        queue->k++;
        BinomialNode* temp[queue->k];
        int i;
        for(i = 0; i < queue->k-1; i++)
            temp[i] = queue->children[i];
        temp[queue->k-1] = in;
        for(i = 0; i < queue->k; i++)
            queue->children[i] = temp[i];
        if(BQ[queue->k] == NULL)
        {
            BQ[queue->k] = queue;
            return;
        }
        else
            merge(queue, BQ[queue->k]);
    }
    void BinomialTree::print(BinomialNode *root, int tab)
    {
        if(root == NULL)
            return;
        int i;
        for(i = 0; i < tab*5; i++) cout << " ";
        cout << root->data << endl;
        for(i = 0; i < root->k; i++) print(root->children[i], tab+1);
    }
}

So when I try to simply compile my code using "g++ Asg5.cpp" I receive the following error
 
 
 
/tmp/cczhpSGO.o: In function 'main':
 
 
Asg5.cpp:(.text+0x2fb): undefined reference to 'BinomialTree::insert(int)'
 
 
collect2: ld returned 1 exit status
 
 
If anyone's wondering why I'm not using a makefile, my professor simply wants to type g++ <.cpp with main()> to compile..
 
Anyway here's my code I really appreciate the assistance!
 
Asg5.cpp
 
#include "BinomialTree.h"
#include "BinomialNode.h"
#include <iostream>
#include <vector>
#include <fstream>
#include <sstream>
#include <stdlib.h>
#include <string>
#include <stdio.h>

using namespace std;
int main(int argc, char* argv[])
{
    //input handling
    if(argc != 2)
    {
        cout << "Incorrect Usage. \n Example: ./a.out <filename>" << endl;
        exit(1);
    }
    BinomialTree *tree = new BinomialTree(); 

    char *buffer;
    char *token;
    //read file into buffer.**************************************
    string input;
    ifstream file;
    file.open(argv[1]);
    if(file.is_open())
    {
        string str;
        while(file.good())
        {
            getline(file,str);
            input += " " + str;
        }
    }
    else{
        cout << "File not found"<< endl;
        return 1;
    }
    file.close();

    int buf;
    stringstream ss(input);

    vector<int> tokens;

    while(ss >> buf)
    {
        tokens.push_back(buf);
    }
    int i = 0;
    for(i = 0; i < tokens.size(); i++)
        tree->insert(tokens[i]);
    //end file reading *******************************************
    delete tree;
}
 
BinomialNode.h
 
#ifndef _BINOMIALNODE_H_
#define _BINOMIALNODE_H_
#include "BinomialTree.h"
class BinomialNode
{
    public: 
        int k;
        BinomialNode *children[20];
        int data;

        BinomialNode();
};
#endif
 
BinomialNode.cpp
 
class BinomialNode
{   
    BinomialNode::BinomialNode(int n)
    {   
        this->k = 0;
        this->data = n;
    }
}
 
BinomialTree.h
 
#ifndef _MULTIMAP_H_
#define _MULTIMAP_H_
#include "BinomialNode.h"

class BinomialTree
{
    public:
        BinomialNode * BQ[20];


        void insert(int n);
        void merge(BinomialNode *queue, BinomialNode *in, int k);
        void print(BinomialNode *root, int tab);
};
#endif
 
BinomialTree.cpp
 
#include "BinomialNode.h"
#include "BinomialTree.h"
#include <iostream>
#include <cstdlib>


class BinomialTree
{
    void BinomialTree::insert(int n)
    {
        BinomialNode *in = new BinomialNode(n);
        if(BQ[0] == NULL)
        {
            BQ[0] = in;
            return;
        }
        else
            merge(BQ[0], in, 0);
    }
    void BinomialTree::merge(BinomialNode *queue, BinomialNode *in, int k)
    {
        if(queue == NULL)
        {
            BQ[k] = in;
            return;
        }
        if(n == NULL)
        {
            BQ[k] = queue;
            return;
        }
        if(queue->data > in->data)
        {   
            merge(in, queue);
            return;
        }
        queue->k++;
        BinomialNode* temp[queue->k];
        int i;
        for(i = 0; i < queue->k-1; i++)
            temp[i] = queue->children[i];
        temp[queue->k-1] = in;
        for(i = 0; i < queue->k; i++)
            queue->children[i] = temp[i];
        if(BQ[queue->k] == NULL)
        {
            BQ[queue->k] = queue;
            return;
        }
        else
            merge(queue, BQ[queue->k]);
    }
    void BinomialTree::print(BinomialNode *root, int tab)
    {
        if(root == NULL)
            return;
        int i;
        for(i = 0; i < tab*5; i++) cout << " ";
        cout << root->data << endl;
        for(i = 0; i < root->k; i++) print(root->children[i], tab+1);
    }
}

原文：https://stackoverflow.com/questions/36783909