Kivo360 Kivo360 - 5 months ago 74
Linux Question

G++ undefined reference to class::function

I'm finally pretty desperate. So, in my c++ class we were instructed to use classes. We'd have the header file declare the class and functions while a separate .cpp file implements the it. Things should be working, but they're not and no solutions on the web seem to be working for me. I'm using the G++ compiler on linux for this, and it doesn't seem to work on either IDE's or the normal command line.

The error I'm getting in my TBook.h is this:

/usr/lib/gcc/x86_64-linux-gnu/4.6/../../../x86_64-linux-gnu/crt1.o: In function `_start':
(.text+0x20): undefined reference to `main'
/tmp/ccxqI6An.o: In function `TBook::TBook()':
TBook.cpp:(.text+0x3b): undefined reference to `Telephone::Telephone()'
TBook.cpp:(.text+0x100): undefined reference to `Telephone::Telephone()'
TBook.cpp:(.text+0x132): undefined reference to `Telephone::allNum(std::basic_string<char, std::char_traits<char>, std::allocator<char> >)'
TBook.cpp:(.text+0x182): undefined reference to `Telephone::~Telephone()'
TBook.cpp:(.text+0x191): undefined reference to `Telephone::~Telephone()'
TBook.cpp:(.text+0x2b3): undefined reference to `Telephone::~Telephone()'
TBook.cpp:(.text+0x2e6): undefined reference to `Telephone::~Telephone()'
TBook.cpp:(.text+0x2fa): undefined reference to `Telephone::~Telephone()'
/tmp/ccxqI6An.o:TBook.cpp:(.text+0x370): more undefined references to `Telephone::~Telephone()' follow
/tmp/ccxqI6An.o: In function `TBook::write()':
TBook.cpp:(.text+0x4e1): undefined reference to `Telephone::getNumber()'
TBook.cpp:(.text+0x506): undefined reference to `Telephone::getAreaCode()'
TBook.cpp:(.text+0x53a): undefined reference to `Telephone::getName()'
/tmp/ccxqI6An.o: In function `TBook::lookup(std::basic_string<char, std::char_traits<char>, std::allocator<char> >)':
TBook.cpp:(.text+0x6d4): undefined reference to `Telephone::getName()'
TBook.cpp:(.text+0x79e): undefined reference to `Telephone::Telephone(int, std::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::basic_string<char, std::char_traits<char>, std::allocator<char> >)'
/tmp/ccxqI6An.o: In function `TBook::print()':
TBook.cpp:(.text+0x880): undefined reference to `Telephone::getName()'
TBook.cpp:(.text+0x8e0): undefined reference to `Telephone::getNumber()'
TBook.cpp:(.text+0x8ff): undefined reference to `Telephone::getAreaCode()'
collect2: ld returned 1 exit status
[Finished in 0.3s with exit code 1]


I'm kind of not liking that the file is not receiving any of the Telephone class's methods. Here's what the code looks like for TBook.h:

#ifndef TBOOK_H
#define TBOOK_H

#include "Telephone.h"

class TBook{
private:
Telephone rolodex[10];
int current;
int max;
public:
TBook();
~TBook();
void add(Telephone);
void write();
bool is_full();
void print();
void check();
Telephone lookup(string);

};

#endif


And this is what TBook.cpp looks like:

#include <iostream>
#include <fstream>
#include <string>

#include "TBook.h"
#include "Telephone.h"


using namespace std;

TBook::TBook(){
current = 0;
max = 9;

cout << "Hello" << endl;

string line;
ifstream myfile ("rolodex.txt");
if (myfile.is_open()){
while ( getline (myfile,line) ){
cout << line << endl;
Telephone t;
t.allNum(line);
add(t);

}
myfile.close();
}else if (!myfile.is_open()){
ofstream myfile;
myfile.open ("rolodex.txt");
myfile << "This is an empty file (Relatively).";
myfile.close();
}
}

TBook::~TBook(){

}

void TBook::add(Telephone tel){
if (!is_full()){
rolodex[current] = tel;
current++;
}
}

void TBook::write(){
ofstream myfile;
myfile.open ("rolodex.txt");
for (int i = 0; i < current; ++i)
{
myfile << rolodex[i].getName() << "," << rolodex[i].getAreaCode() << "," << rolodex[i].getNumber() << "\n";
}
myfile.close();
}

bool TBook::is_full(){
if (current <= max){
return false;
}
return true;
}

Telephone TBook::lookup(string lookName){
for (int i = 0; i < current; ++i){
if (rolodex[i].getName() == lookName){
return rolodex[i];
}
}
return Telephone(100, "", "1000000");
}

void TBook::print(){
//Print the vairables
for (int i = 0; i < current; ++i){
cout << "Name: " << rolodex[i].getName() << endl;
cout << "Number: (" << rolodex[i].getAreaCode() << ") " << rolodex[i].getNumber() << endl;
}

}

void TBook::check(){
cout << "the message" << endl;
}


Since the problem seems to be arising with the Telephone class, I figure I should also show that code too


Telephone.h


..

#ifndef TELEPHONE_H
#define TELEPHONE_H

#include <iostream>
#include <string>


using std::string;

class Telephone{
private:
string name;
string num;
int areaCode;
public:
Telephone(int, string, string);
Telephone();
~Telephone();
bool setAreaCode(int);

//Setters

void setName(string);
void setNumber(string);
bool allNum(string);

//Getters
string getName();
string getNumber();
int getAreaCode();

//Checks
bool checkX(int);
bool checkY(int);


};

#endif



Telephone.cpp


..

#include <iostream>
#include <string>
#include <stdio.h>
#include <stdlib.h>

#include "Telephone.h"

using namespace std;

Telephone::Telephone(){
areaCode = 0
name = "";
num = "";
}

Telephone::Telephone(int aCode, string nam, string number){
areaCode = aCode;
name = name;

}

Telephone::~Telephone(){
//Nope Nada
}

bool Telephone::allNum(string all){
size_t found = all.find_first_of(",");

//
string first = all.substr(0, found);
string second = all.substr((found)+1, found+1);
string third = all.substr( all.find_last_of(",")+1, all.length());
int x, y;
//convert string to int values
if(third.length() == 7){
x = atoi(third.substr(0,3).c_str()),
y = atoi(third.substr(3,4).c_str());
}else{
cerr << "Your phone number is not valid" << endl;
}
int ac = atoi(second.substr(0, second.length()).c_str());

setName(first);
if (!setAreaCode(ac)){
setAreaCode(100);
return true;

}
if (!checkX(x) || !checkY(y)){
setNumber("1000000");
}else{
setNumber(third);
}

cerr << "The info provided is not valid" << endl;
return false;
}

void Telephone::setNumber(string number){
num = number;
}

bool Telephone::setAreaCode(int aCode){
if(aCode >= 100 && aCode <= 999){
areaCode = aCode;
return true;
}
return false;
}

void Telephone::setName(string theName){
name = theName;
}

bool Telephone::checkX(int x){
if(x >= 100 && x <= 999){
return true;
}
cerr << "First three digits are not valid" << endl;
return false;
}

bool Telephone::checkY(int y){
if(y >= 0000 && y <= 9999){
return true;
}
cerr << "Last four digits are not valid" << endl;
return false;
}



//Getters
string Telephone::getName(){
return name;
}

string Telephone::getNumber(){
return num;
}

int Telephone::getAreaCode(){
return areaCode;
}


And my main file (also called test.cpp) looks like this:


test.cpp


#include <iostream>
#include <string>
#include "TBook.h"
#include "Telephone.h"

using namespace std;


int main(int argc, char const *argv[])
{
//Create a Rolodex
TBook addressBook;

return 0;
}


I'm also getting this error with test.cpp

/tmp/ccl8anRb.o: In function `main':
test.cpp:(.text+0x24): undefined reference to `TBook::TBook()'
test.cpp:(.text+0x38): undefined reference to `TBook::~TBook()'
collect2: ld returned 1 exit status


I think this is mostly a compiling error, but I'm still not sure, and I feel like I'm the setup of the meme "My code doesn't work, and I don't know why." Usually I would bash the code and try different methods until it works, but I simply don't have the time. I therefore need your help.

Answer Source

This is a linker error. Try:

g++ test.cpp Telephone.cpp -o test

Basically, the linker is complaining about functions you used but didn't provide an implementation for. To see all the steps the compiler performs for you, throw in a -v:

g++ -v test.cpp Telephone.cpp -o test
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