This question already has answers here:
What is an undefined reference/unresolved external symbol error and how do I fix it?
(39 answers)
Closed 8 years ago.
I was just trying to see if I can read a text file and display but I have this error:
2 error LNK2019: unresolved external symbol "public: void __thiscall
WeatherReport::displayReport(void)"
(?displayReport#WeatherReport##QAEXXZ) referenced in function _main
Can anyone explain me what is causing this, why this is happening and how to fix this problem?
#include<fstream>
#include<iomanip>
#include<stdio.h>
#include<cmath>
#include<iostream>
using namespace std;
class WeatherReport
{
WeatherReport friend monthEnd(WeatherReport, WeatherReport);
private:
int dayofMonth;
int highTemp;
int lowTemp;
double amoutRain;
double amoutSnow;
public:
WeatherReport(int Day = 0);
void setValues(int, int, int, double, double);
void getValues();
void displayReport();
}
void WeatherReport::setValues(int dom, int ht, int lt, double ar, double as)
{
dayofMonth = dom;
highTemp = ht;
lowTemp = lt;
amoutRain = ar;
amoutSnow = as;
}
int main()
{
const int DAYS = 30;
WeatherReport day[DAYS];
WeatherReport summary;
int i = 0;
ifstream inFile;
inFile.open("WeatherTest.txt");
if (!inFile)
cout << "File not opended!" << endl;
else
{
int dom, ht, lt;
double ar, as;
while (inFile >> dom >> ht >> lt >> ar >> as)
{
day[i].setValues(dom, ht, lt, ar, as);
i++;
}
inFile.close();
for (int i = 0; i < DAYS; i++)
{
day[i].displayReport();
//read one line of data from the file
//pass the data to setValues to initialize the object
}
system("PAUSE");
return 0;
}
Your displayReport does not have a function body, and as such does not have an external symbol referencing it, hence the error.
Add a function body for displayReport, and the issue will go away:
void WeatherReport::displayReport()
{
//Place your code here.
}
The following code can be used to reproduce this error:
[header file- test.h]:
#include "StdAfx.h"
void someOtherFunction();
void someFunction(string thisVar);
[code file- test.cpp]:
#include "StdAfx.h"
#include "test.h"
void someOtherFunction()
{
printf("Hello World!");
}
[function body for someFunction(string thisVar) is missing!]
The error speaks for itself
LNK2019: unresolved external symbol "public: void __thiscall WeatherReport::displayReport(void)
It can't find the definition for WeatherReport::displayReport(). I see its declaration in your code, but there's no definition anywhere. Either you didn't write a definition, or you provided it and didn't link the .cpp file that it's in. I'm guessing the former.
Seems like displayReport() does not have a body - it is only declared, but not defined. Add the following:
void WeatherReport::displayReport()
{
//your code
}
Related
This question already has answers here:
What is an undefined reference/unresolved external symbol error and how do I fix it?
(39 answers)
Closed 7 years ago.
I'm a visual studio 2015 c++ newby who's trying to write some game code at home.
I'm getting this link error:
LNK2019 unresolved external symbol "public: class std::basic_string,class std::allocator > __thiscall display_utils::fit_int_2(int)" (?fit_int_2#display_utils##QAE?AV?$basic_string#DU?$char_traits#D#std##V?$allocator#D#2##std##H#Z) referenced in function "public: void __thiscall bat_stats::disp_bat_stats(struct bat_stats::bat_stats_typ)" (?disp_bat_stats#bat_stats##QAEXUbat_stats_typ#1##Z)
It apparently doesn't like the string I'm using to access the returned string from function fit_int_2. I've google searched for a solution, but can't find anything that fixes my problem. Note that the code compiled and linked before i I added the fit_int_2 call. Thanks in advance if you can help me out. The code is below:
bat_stats.h
#pragma once
class bat_stats
{
public:
struct bat_stats_typ
{
int gm;
int ab;
int ht;
int dbl;
int trpl;
int hr;
int rbi;
int sb;
int cs;
int bb;
int ibb;
int sf;
int sac;
int k;
int gidp;
int err;
float ave;
float slg;
float obp;
};
void disp_bat_hdr();
void disp_bat_stats( bat_stats_typ );
private:
int dummy;
};
bat_stats.cpp
#include <iostream>
using std::cout;
std::cin;
#include <string>
using std::string;
#include "bat_stats.h"
#include "display_utils.h"
void bat_stats::disp_bat_hdr()
{
cout << " G AB H 2B 3B HR RBI SB CS BB IW SF SH K GDP E AVE SLG OBP\n";
}
void bat_stats::disp_bat_stats( bat_stats_typ bat )
{
display_utils dut;
string s;
s = dut.fit_int_2( bat.gm ); // <- the problem is here!
cout << s << bat.gm << " ";
cout << bat.ab << "\n\n";
}
display_utils.h
#pragma once
#include <string>
using std::string;
class display_utils
{
public:
void insert_5_lines();
string fit_int_2( int );
private:
int dummy;
};
display_utils.cpp
#include <iostream>
using std::cout;
#include "display_utils.h"
void display_utils::insert_5_lines()
{
cout << "\n\n\n\n\n";
}
string fit_int_2(int i0)
{
string s0 = "";
if (i0 < 10)
{
s0 = " ";
}
return s0;
}
You need to change
string fit_int_2(int i0)
to
string display_utils::fit_int_2(int i0)
(You need to define the member function - currently you're defining an unrelated global function.)
Hello I am having some troubles with linking header files that contains templates. I have heard that using namespace could resolve this linking issue, but I could not get it to work. Thanks in advance.
//utility.h
#ifndef _UTILITY_H_
#define _UTILITY_H_
#include<iostream>
#include<string>
#include<vector>
using namespace std;
namespace utility
{
template<typename T>
void space_b4(T &value, int &max_num_length);
template<class T>
string doub_to_str(T &d); //Converting double to string.
}
using namespace utility;
template<class T>
string doub_to_str(T &d) //Converting double to string.
{
stringstream ss;
ss << d;
return ss.str();
}
template<typename T>
void space_b4(T &value, int &max_num_length) //This function adds space before an element if the number of digits of this element is less than the maximum number.
{
int d = max_num_length - doub_to_str(value).length();
for (int a = 0; a < d / 2; a++)
{
cout << " ";
}
}
#endif
Here is my main cpp file: Data management.cpp
//Data management.cpp
#include <iostream>
#include"utility.h"
using namespace std;
using namespace utility;
int main()
{
double a;
int max;
max = 10;
utility::space_b4(a, max);
}
Here are the error messages:
1>Data management.obj : error LNK2019: unresolved external symbol "void __cdecl utility::space_b4<double>(double &,int &)" (??$space_b4#N#utility##YAXAANAAH#Z) referenced in function _main
1>C:\Users\liuxi_000\Documents\C++\Final project_test\Final Project\Debug\Final Project.exe : fatal error LNK1120: 1 unresolved externals
You declare template functions utility::space_b4 and utility::doub_to_str, but the definitions are in global namespace.
To fix this, move the definitions into the namespace utility { } block:
namespace utility
{
template<typename T>
void space_b4(T &value, int &max_num_length);
template<class T>
string doub_to_str(T &d); //Converting double to string.
}
namespace utility
{
template<class T>
string doub_to_str(T &d) //Converting double to string.
{
stringstream ss;
ss << d;
return ss.str();
}
template<typename T>
void space_b4(T &value, int &max_num_length) //This function adds space before an element if the number of digits of this element is less than the maximum number.
{
int d = max_num_length - doub_to_str(value).length();
for (int a = 0; a < d / 2; a++)
{
cout << " ";
}
}
}
I'm trying to add elements to a vector in my program. But I'm not sure if I'm doing it right. So far what I have below does not work. I get an error that says:
error LNK2019: unresolved external symbol "public: __thiscall MySet::MySet(void)" (??0MySet##QAE#XZ) referenced in function _main
Here is my code:
#include <iostream>
#include <map>
#include <vector>
using namespace std;
class MySet{
public:
vector<int> elements;
MySet();
void addElement(int value);
int removeElement(int index);
int sum();
int size();
};
void MySet::addElement(int value){
elements.push_back(value);
}
int main(int argc, char *argv[]){
int value;
MySet set;
cout << "Enter your numbers " << endl;
cin >> value;
while(value != -1){
set.addElement(value);
}
system("PAUSE");
}
first:
You never define your MySet ctor.Define it or remove your declaration of MySet().
second:
cin>>value out of while loop,so just input once,you maybe want write code like this:
EDIT:
while(cin >> value){
if(value==-1)
break;
set.addElement(value);
}
This question already has answers here:
What is an undefined reference/unresolved external symbol error and how do I fix it?
(39 answers)
Closed 8 years ago.
I'm a new guy in C++ and I could not understand where I am wrong in this code. I take this error:
ClCompile:
1> Student.cpp
1>Student.obj : error LNK2019: unresolved external symbol "public: void __thiscall Student::setExamGrade(int,int)" (?setExamGrade#Student##QAEXHH#Z) referenced in function _main
1>c:\users\administrator\documents\visual studio 2010\Projects\LAB1\Debug\LAB1.exe : fatal error LNK1120: 1 unresolved externals
1>
1>Build FAILED.
Could you please help me? Code here:
Student.h
#ifndef STUDENT_H
#define STUDENT_H
#include <string>
using namespace std;
class Student
{
private:
int ID;
string name;
int *exams;
public:
Student();
Student(int ID, string name);
void setExamGrade(int index, int grade);
int getOverallGrade();
void display();
};
#endif
Student.cpp
#include "Student.h"
#include <iostream>
using namespace std;
int total;
int count;
int average;
int exams[3];
void main() {
Student *s = new Student(123, "John");
s->setExamGrade(0, 80);
s->setExamGrade(1, 60);
s->setExamGrade(2, 95);
s->display();
delete s;
}
Student :: Student()
{
ID = 0;
name = "";
}
Student :: Student(int num, string text)
{
this->ID = num;
this->name = text;
}
void setExamGrade(int index, int grade)
{
exams[index] = grade;
total += exams[index];
count = index +1;
}
int getOverallGrade()
{
average = total/count;
return average;
}
void Student :: display()
{
cout << "ID:" << ID << "NAME:" << name << "GRADE:" << endl;
}
You declare the method:
void setExamGrade(int index, int grade);
Inside the class Student
But you don't define the method. You do define a function with the same name.
void setExamGrade(int index, int grade)
{ // STUFF
}
But that is not a method definition,
I think you missed the Student :: before setExamGrade and getOverallGrade.
You have it defined like so
void setExamGrade(int index, int grade) { .. }
That is just a function by itself, and it doesn't belong to a class. You want
void Student::setExamGrade(int index, int grade) { .. }
"unresolved external symbol" means the body of the code in question is not found by the linker.
In this case it's the Student::setExamGrade method whose body is not found.
Your code appears to have defined a function setExamGrade but this has not been flagged as a Student:: method (in the way that you have successfully done for Student::display)
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Closed 10 years ago.
I have looked and I know there are other answers out there but none of them seem to give me what i'm looking for so please don't report this as a "repost"
I'm getting the unresolved external symbol "public: __thiscall" error in my C++ code and i'm about to kick it out the window and just fail my C++ class. Please help me!!!!
My checking account header file
#include "BankAccount.h"
class CheckingAccount
{
private:
int numOfWithdrawls;
double serviceFee;
int AccountBal;
public:
bool withdraw (double wAmmt);
BankAccount CA;
CheckingAccount();
CheckingAccount(int accountNum);
};
and its CPP file
#include <iostream>
using namespace std;
#include "CheckingAccount.h"
CheckingAccount::CheckingAccount()
{
CA;
numOfWithdrawls = 0;
serviceFee = .50;
}
CheckingAccount::CheckingAccount(int accountNum)
{
CA.setAcctNum (accountNum);
numOfWithdrawls = 0;
serviceFee = .50;
}
bool CheckingAccount::withdraw (double wAmmt)
{
numOfWithdrawls++;
if (numOfWithdrawls < 3)
{
CA.withdraw(wAmmt);
}
else
{
if (CA.getAcctBal() + .50 <=0)
{
return 0;
}
else
{
CA.withdraw(wAmmt + .50);
return 1;
}
}
}
My BankAccount header file
#ifndef BankAccount_h
#define BankAccount_h
class BankAccount
{
private:
int acctNum;
double acctBal;
public:
BankAccount();
BankAccount(int AccountNumber);
bool setAcctNum(int aNum);
int getAcctNum();
double getAcctBal();
bool deposit(double dAmmt);
bool withdraw(double wAmmt);
};
#endif
My BankAccount CPP file
#include <iostream>
using namespace std;
#include "BankAccount.h"
BankAccount::BankAccount(int AccoutNumber)
{
acctNum = 00000;
acctBal = 100.00;
}
bool BankAccount::setAcctNum(int aNum)
{
acctNum = aNum;
return true;
}
int BankAccount::getAcctNum()
{
return acctNum;
}
double BankAccount::getAcctBal()
{
return acctBal;
}
bool BankAccount::deposit(double dAmmt)
{
acctBal += dAmmt;
return true;
}
bool BankAccount::withdraw(double wAmmt)
{
if (acctBal - wAmmt <0)
{
return 0;
}
else
{
acctBal -= wAmmt;
return 1;
}
}
My error:
1>BankAccountMain.obj : error LNK2019: unresolved external symbol "public: __thiscall BankAccount::BankAccount(void)" (??0BankAccount##QAE#XZ) referenced in function "public: __thiscall SavingsAccount::SavingsAccount(void)" (??0SavingsAccount##QAE#XZ)
1>CheckingAccount.obj : error LNK2001: unresolved external symbol "public: __thiscall BankAccount::BankAccount(void)" (??0BankAccount##QAE#XZ)
The "__thiscall" is noise. Read on. The error messages are complaining about BankAccount::BankAccount(void). The header file says that BankAccount has a default constructor, but there's no definition for it.
In your BankAccount class you declare a constructor that takes no arguments
BankAccount();
but you do not implement it. This is why the linker cannot find it. Provide an implementation for this constructor in your .cpp file and the link step should work.