[RESOLVED] Unresolved external symbol

perhaps this can be a very popular error, but i´m beginner and i not used to see problems like this

Code:

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#include <stdio.h>
#include <tchar.h>

#include <iostream>
#include <string>
#include <fstream>// enable writing to and reading from files
#include <cstdlib>
#include <time.h>

using namespace std;


class Person
{   

public:

  //Constructor and Destructor Methods

  Person(){cout<<"\n\tBuilding a Person.";};
  ~Person(){cout<<"\n\tDestroying a Person.";};

  //Accessor Methods

  string getName      (){ return Name; }
  string getLocation  (){ return Location; }
  string getAge        (){ return Age; }
  string getOccupation (){ return Occupation; }

  void setName      (string Name)      { Name = Name; }
  void setLocation  (string Location)  { Location = Location; }
  void setAge        (string Age)        { Age = Age; }
  void setOccupation (string Occupation) { Occupation = Occupation; }
private:

  string Name,
        Location,
        Age,
        Occupation;


};



//Function prototypes

void createperson();
void editperson();
void displayperson();
void saveperson();
void loadperson();



int main (int argc, char *argv[])
{
 
  Person* cg = new Person();

  char choose[10] = "";
 
    cout<<"\n\t Personnel database 1.0\n";

    //system display ("CLS");

    while (choose [0] != 'q')
    {
        system ("CLS");
        cout<<"\n\t---------------------Main Menu---------------------\n";
        cout<<"\n\t| |\n";
        cout<<"\n\t| (c) Create person |\n";
        cout<<"\n\t| (E) edit information |\n";
        cout<<"\n\t| (D) display person |\n";
        cout<<"\n\t| (S) Save person |\n";
        cout<<"\n\t| (L) Load person |\n";
        cout<<"\n\t| (Q) quit |\n";
        cout<<"\n\t| |\n";
        cout<<"\n\t---------------------------------------------------\n\n\t";
        cin>>choose;
        //system ("CLS");
        switch (choose [0])
        {
            //system ("CLS");
        case 'c': createperson(); break;
        case 'e': editperson(); break;
        case 'd': displayperson(); system ("pause"); break;
        case 's': saveperson(); break;
        case 'l': loadperson(); break;
        case 'q': cout<<"\n\tExiting main menu..."; break;
        default :"\n\tInvalid input!";
        }
     
    }

    system ("pause");
      return 0;

}

//Function´s scope


void createperson()
{

  Person* cg = new Person();
 
}

void editPerson()
{
    Person* cg = new Person();
 
  string TEMP;
    system ("CLS");
    cout<<"\n\n\t---------------------EDIT person ---------------------------";

    cout<<"\n\t Name: ";
    getline (cin,TEMP);
    cg->setName(TEMP);

    cout<<"\n\t Location ";
    getline (cin,TEMP);
    cg->setLocation(TEMP);

    cout<<"\n\t Age: ";
    getline (cin,TEMP);
    cg->setAge(TEMP);

    cout<<"\n\t Occupation: ";
    getline (cin,TEMP);
    cg->setOccupation(TEMP);
}

void displayPerson()
{
  Person* cg = new Person();

    system("CLS");
    cout<<"\n\n\t---------------------person information----------------------";
    cout<< "\n\tName: "      , cg->      getName();
    cout<< "\n\tOccupation:" , cg->  getLocation();
    cout<< "\n\tLocation: "  , cg->        getAge();
    cout<< "\n\tReferences:" , cg-> getOccupation();
    cout<<"\n\n\t---------------------------------------------------------------\n\n";
}

void savePerson()
{
  Person* cg = new Person();


    try
    {
        ofstream DATAFILE;
        DATAFILE.open("Data1.file",ios::out);

        DATAFILE <<cg->getName      ()<<"\n";
        DATAFILE <<cg->getLocation ()<<"\n";
        DATAFILE <<cg->getAge  ()<<"\n";
        DATAFILE <<cg->getOccupation ()<<"\n";

        DATAFILE.close(); //Prevents data from getting corrupt incase of sudden shutdown
        cout<<"\n\t Success! Data was saved to file.";
    }
    catch (exception x)
    {
        cout<<"\n\t File Error! Could not SAVE PERSON.";
    }
}

void loadperson()
{
  Person* cg = new Person();

    try
    {
        string TEMP;
        ifstream DATAFILE;
        DATAFILE.open("Data1.file",ios::in);
        getline (DATAFILE,TEMP);

        cg->setName (TEMP);
        getline (DATAFILE,TEMP);

        cg->setLocation (TEMP);
        getline (DATAFILE,TEMP);

        cg->setAge (TEMP);
        getline (DATAFILE,TEMP);

        cg->setOccupation (TEMP);
        DATAFILE.close();
    }
    catch (exception x)
    {
        cout<<"\n\t File Error! Unable to load data.";
    }
}

---

erros list:

Code:

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Error  1  error LNK2019: unresolved external symbol "void __cdecl saveperson(void)" (?saveperson@@YAXXZ) referenced in function _main  H:\Cry_Dev\Programming\C++\Using_class_ in_ c++\Using_class_ in_ c++\Using_class_ in_ c++.obj
Error  2  error LNK2019: unresolved external symbol "void __cdecl displayperson(void)" (?displayperson@@YAXXZ) referenced in function _main  H:\Cry_Dev\Programming\C++\Using_class_ in_ c++\Using_class_ in_ c++\Using_class_ in_ c++.obj
Error  3  error LNK2019: unresolved external symbol "void __cdecl editperson(void)" (?editperson@@YAXXZ) referenced in function _main  H:\Cry_Dev\Programming\C++\Using_class_ in_ c++\Using_class_ in_ c++\Using_class_ in_ c++.obj
Error  4  error LNK1120: 3 unresolved externals  H:\Cry_Dev\Programming\C++\Using_class_ in_ c++\Debug\Using_class_ in_ c++.exe  1

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what i can do to fit this problem?

c++ is case sensitive. ie displayperson is different to displayPerson.

Code:

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void editperson();
void displayperson();
void saveperson();

...

void displayPerson()
{

---

You need to check that the case of your function declarations are the same as those of your function definitions and that they are also the same where the function is used.

good observation!!! i ´ll take a look! thanks!

the program "works well", but it no saves , no displays and no load the information that i type.

Code:

---


// Using_class_ in_ c++.cpp : Defines the entry point for the console application.
//

#include <stdio.h>
#include <tchar.h>

#include <iostream>
#include <string>
#include <fstream>// enable writing to and reading from files
#include <cstdlib>
#include <time.h>

using namespace std;


class Person
{   

public:

        //Constructor and Destructor Methods

        Person(){cout<<"\n\tBuilding a Person.";};
  ~Person(){cout<<"\n\tDestroying a Person.";};

        //Accessor Methods

        string getName      (){ return Name; }
        string getLocation  (){ return Location; }
        string getAge        (){ return Age; }
        string getOccupation (){ return Occupation; }

        void setName      (string Name)      { Name = Name; }
        void setLocation  (string Location)  { Location = Location; }
        void setAge        (string Age)        { Age = Age; }
        void setOccupation (string Occupation) { Occupation = Occupation; }
private:

        string Name,
                  Location,
                  Age,
                  Occupation;


};



//Function prototypes

void createperson();
void editperson();
void displayperson();
void saveperson();
void loadperson();



int main (int argc, char *argv[])
{
       
        Person* cg = new Person();

        char choose[10] = "";
 
    cout<<"\n\t Personnel database 1.0\n";

    //system display ("CLS");

    while (choose [0] != 'q')
    {
        system ("CLS");
        cout<<"\n\t---------------------Main Menu---------------------\n";
        cout<<"\n\t| |\n";
        cout<<"\n\t| (c) Create person |\n";
        cout<<"\n\t| (E) edit information |\n";
        cout<<"\n\t| (D) display person |\n";
        cout<<"\n\t| (S) Save person |\n";
        cout<<"\n\t| (L) Load person |\n";
        cout<<"\n\t| (Q) quit |\n";
        cout<<"\n\t| |\n";
        cout<<"\n\t---------------------------------------------------\n\n\t";
        cin>>choose;
        //system ("CLS");
        switch (choose [0])
        {
            //system ("CLS");
        case 'c': createperson(); break;
        case 'e': editperson(); break;
        case 'd': displayperson(); system ("pause"); break;
        case 's': saveperson(); break;
        case 'l': loadperson(); break;
        case 'q': cout<<"\n\tExiting main menu..."; break;
        default :"\n\tInvalid input!";
        }
     
    }

          system ("pause");
      return 0;

}

//Function´s scope


void createperson()
{

        Person* cg = new Person();
       
}

void editperson()
{
    Person* cg = new Person();
       
        string TEMP;
    system ("CLS");
    cout<<"\n\n\t---------------------EDIT person ---------------------------";

    cout<<"\n\t Name: ";
        cin.ignore();
    getline (cin,TEMP);
    cg->setName(TEMP);

    cout<<"\n\t Location ";
    getline (cin,TEMP);
    cg->setLocation(TEMP);

    cout<<"\n\t Age: ";
    getline (cin,TEMP);
    cg->setAge(TEMP);

    cout<<"\n\t Occupation: ";
    getline (cin,TEMP);
    cg->setOccupation(TEMP);
}

void displayperson()
{
        Person* cg = new Person();

    system("CLS");
    cout<<"\n\n\t---------------------person information----------------------";
    cout<< "\n\tName: "      , cg->      getName();
    cout<< "\n\tOccupation:" , cg->  getLocation();
    cout<< "\n\tLocation: "  , cg->        getAge();
    cout<< "\n\tReferences:" , cg-> getOccupation();
    cout<<"\n\n\t---------------------------------------------------------------\n\n";
}

void saveperson()
{
        Person* cg = new Person();


    try
    {
        ofstream DATAFILE;
        DATAFILE.open("Data1.file",ios::out);

        DATAFILE <<cg->getName      ()<<"\n";
        DATAFILE <<cg->getLocation ()<<"\n";
        DATAFILE <<cg->getAge  ()<<"\n";
        DATAFILE <<cg->getOccupation ()<<"\n";

        DATAFILE.close(); //Prevents data from getting corrupt incase of sudden shutdown
        cout<<"\n\t Success! Data was saved to file.";
    }
    catch (exception x)
    {
        cout<<"\n\t File Error! Could not SAVE PERSON.";
    }
}

void loadperson()
{
        Person* cg = new Person();

    try
    {
        string TEMP;
        ifstream DATAFILE;
        DATAFILE.open("Data1.file",ios::in);
        getline (DATAFILE,TEMP);

        cg->setName (TEMP);
        getline (DATAFILE,TEMP);

        cg->setLocation (TEMP);
        getline (DATAFILE,TEMP);

        cg->setAge (TEMP);
        getline (DATAFILE,TEMP);

        cg->setOccupation (TEMP);
        DATAFILE.close();
    }
    catch (exception x)
    {
        cout<<"\n\t File Error! Unable to load data.";
    }
}

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Quote:

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the program "works well", but it no saves , no displays and no load the information that i type.

---

Well it now compiles and links, but I would hardly claim that it 'works well' when it doesn't load, save or display the information!

What debugging of the program have you done? Have you traced through the program using the debugger to see where your program deviates from that which you expected?

Hint. The scope of variables defined within a function are local to that function. So if you define the same variable (say *cg) in several functions, each of these definitions refer to a different 'cg' even though they have the same name.

Also, you have memory leaks as you are using 'new' but are not deleting the memory allocated anywhere.

if i retire the objects from the functions i have some problems like "cg is undefined"
how i can do to make a global object for all the functions?

ok, i´ve made a global object before main method
but nothing changed

i my directory was created a file Data1.file how can i read it to check if the data is saved?

Quote:

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Originally Posted by crisdeveloper

i my directory was created a file Data1.file how can i read it to check if the data is saved?

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Notepad? The VC editor?

not. these txt editors only show me a empty txt.

i meam that the program compiles well but not work like i would want. :D

i tried to understand what wrong is happening, but still i don´t know waht i can do. i already try to put the function save inside the function editPerson, but no progress in it.

i´m instaling fileViewPro to open data1.file.

See 2kaud's hint in post #5

Basically, you have a couple of choices. You can either make cg a global variable, or define it in main and pass it as a parameter to each of the used functions.

If you define it at global scope then its definition would be after the definition of the class, but before main. Then in all the functions, the definition for cg would be removed.

Note that you also have a problem with your class

Code:

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void setName      (string Name)      { Name = Name; }

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This doesn't do what you think it does. You need either to have

Code:

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void setName      (string Name1)      { Name = Name1; }

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or

Code:

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void setName      (string Name)      { this->Name = Name; }

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It's usually not a good idea to have the name of parameters the same as class members.

You also need to delete the memory allocated in the createperson function or you have a memory leak.

fileview pro is not for open this kind of file. :(
but the question is not this. the most imoprtant is make the program works welll!!