Where is the undefined reference? [duplicate] - c++

Question

This question already has answers here:
What is an undefined reference/unresolved external symbol error and how do I fix it?
(39 answers)
Closed 3 years ago.
I have a problem!
It shows this error:
"C:\Users\User\AppData\Roaming\JetBrains\CLion 2018.2.4\bin\cmake\win\bin\cmake.exe" --build C:\Users\User\CLionProject\HospitalTest\cmake-build-debug --target HospitalTest -- -j 2
[ 50%] Linking CXX executable HospitalTest.exe
CMakeFiles\HospitalTest.dir/objects.a(main.cpp.obj): In function `main':
C:/Users/User/CLionProject/HospitalTest/main.cpp:9: undefined reference to `CHospitalWard::CHospitalWard()'
C:/Users/User/CLionProject/HospitalTest/main.cpp:23: undefined reference to `CHospitalWard::OnAdd()'
C:/Users/User/CLionProject/HospitalTest/main.cpp:24: undefined reference to `CHospitalWard::OnDelRegNum()'
C:/Users/User/CLionProject/HospitalTest/main.cpp:25: undefined reference to `CHospitalWard::OldestPatient()'
C:/Users/User/CLionProject/HospitalTest/main.cpp:26: undefined reference to `CHospitalWard::OnPrint()'
C:/Users/User/CLionProject/HospitalTest/main.cpp:27: undefined reference to `CHospitalWard::IsInRegNum()'
collect2.exe: error: ld returned 1 exit status
mingw32-make.exe[3]: *** [CMakeFiles\HospitalTest.dir\build.make:85: HospitalTest.exe] Error 1
mingw32-make.exe[2]: *** [CMakeFiles\Makefile2:72: CMakeFiles/HospitalTest.dir/all] Error 2
mingw32-make.exe[1]: *** [CMakeFiles\Makefile2:84: CMakeFiles/HospitalTest.dir/rule] Error 2
mingw32-make.exe: *** [Makefile:117: HospitalTest] Error 2
Code:
///////////////////////////////
#pragma once
#include "Patient.h"
#include <string>
using namespace std;
class CHospitalWard
{
private:
string m_name;
int m_br;
CPatient *m;
public:
CHospitalWard();
CHospitalWard(string, int);
~CHospitalWard(){delete []m;}
void OnAdd();
void OnDelRegNum();
void OnPrint();
int IsInRegNum();
void OldestPatient();
string name_access() {return m_name;}
int br_access() {return m_br;}
};
There are declared like this:
cout<<"Generating..."<<endl;
CHospitalWard f;
int c;
string s;

Answer 1

It is possible that you have included this file, but you have not yet written implementations for these functions. You will need to implement all functions in order for the program to compile.
The minimum implementation for function void DoNothing(); for example would be,
void DoNothing() {}