对“FileReader :：FileReader()”的未定义引用

Question

有人能帮我修一下我的代码吗?这样我就可以编译了。

当我编译它时，会出现一个错误消息“对'FileReader :：FileReader()‘的未定义引用”。

#ifndef SUBFILEREADER_H 
#define SUBFILEREADER_H
#include <string>
#include "FileReader.h"

using namespace std;

class SubFileReader : public FileReader
{
    string sS;
    int iS;
    string sHoldS;
    string siS;

public: 
    SubFileReader();
    string readFile(string file);
};
#endif

#include "SubFileReader.h"
#include "FileReader.h"
#include <iostream>
#include <string>
#include <fstream>
#include <sstream>

using namespace std;

/**
 * class SubFileReader, reads a file and prints it to stdout.
 * 
 * @author Alvin Benedicto
 * @version 2.12.10
 */
SubFileReader::SubFileReader() : FileReader()
{
    sS = "asdf";
    iS = 0;
    siS = "";
}

/**
 * readFile, reads the content of the file into a string and prints the string to standard output.
 * @ param file, string file to be read.
 */
string SubFileReader::readFile(string file)
{
    stringstream ints;

    ifstream in(file.c_str());
    while(getline(in, sS))
    {
        ints << iS++;
        ints >> siS;

        sHoldS += sS + " " + siS + "\n";
    }
    return sS;
}

#include "SubFileReader.h"
#include "FileReader.h"
#include <string>
#include <fstream>
#include <iostream>
using namespace std;

/**
 * main, to test the methods
 * @author Alvin Benedicto
 * @version 2.12.10
 */
int main(int argc, char *argv[])
{
    string str;
    SubFileReader *yz = new SubFileReader();
    str = argv[1];

    ofstream out("MainSubFileReaderTest.txt");
    //cout << xy->readFile(str) << endl;
    out << yz->readFile(str);
}

Answer 1

您需要编译FileReader.cpp，或者链接到包含FileReader::FileReader()定义的哪个库。

顺便说一句，您不需要在客户端代码中使用#include FileReader.h。