Unresolved externals error - what is that?

[jlpurnell]

My code will compile, but it will not debug.

I receive 2 errors.

Error 2 error LNK1120: 1 unresolved externals

Error 1 error LNK2019: unresolved external symbol "int __cdecl menu(void)" (?menu@@YAHXZ) referenced in function _main

Please help! Does LNK1120 refer to a line number? I have never seen these errors before even though I am a beginner.

#include <iostream>  
#include <fstream>  
#include <iomanip>  
#include <cctype>  
using namespace std;  
  
const int DESC_SIZE = 15;								
const int DATE_SIZE = 15;							    
struct InventoryItem								    
{  
    char desc[DESC_SIZE];								
    int quantity;										
    double whlCost;											
    double rtlCost;								 
    char date[DATE_SIZE];								
    int menu();
};   
void addRec(fstream &);							
void dispRec(fstream &);							
void chgRec(fstream &);								



 int InventoryItem::menu()

 {  
	 long selection;
	 selection = menu(); 
     int choice;  
     cout << "Please make a selection, 1 through 4." << endl; 
     cout << "1. Add a new record" << endl;  
     cout << "2. View an exisitng record" << endl;  
     cout << "3. Change an exisitng record" << endl;  
     cout << "4. Exit" << endl;  
     cout << endl;  
     cout <<"Enter your choice (1-4): ";  
     cin >> choice;  
     while(choice < 1 || choice > 4)  

     {  
         cout << "Invaild selection!" << endl;  
         cout << "Please enter your choice (1-4) : "<< endl;  
         cin >> choice;
         
	 }
	
     return choice;  

 }  
 
 
 void addRec(fstream &file)											

 {  

     cout << "Enter the following inventory data:"<<endl;  
     fstream inventory("Inventory.txt", ios::out | ios::binary);  
     InventoryItem record;  

    
     cout << "Description: ";  
     cin.ignore();  

     cin.getline(record.desc, 51);  
     cin >> record.desc;  

     cout << "Quantity: ";  
     cin >> record.quantity;  

     cout << "Wholesale cost: ";  
     cin >> record.whlCost;  

     cout << "Retail price: ";  
     cin >> record.rtlCost; 

     cout << "Date added to inventory (in 00/00/0000 format): ";  
     cin >> record.date;  

	 inventory.write(reinterpret_cast<char *>(&record),sizeof(record));  
     cout << "Record added to file."<<endl;  

     file.close();  

 }  

 void dispRec(fstream &file)  

 {  

     fstream inventory ("Inventory.txt", ios::out | ios::binary);  
     InventoryItem record;  
     long recNum;  
     cout << "Enter the record number of the item to view:";  
     cin >> recNum;  

     inventory.seekg(recNum * sizeof(record), ios::beg);  
     inventory.read(reinterpret_cast<char *>(&record),sizeof(record));  
    
     cout << "Description: " << record.desc << endl;  
     cout << "Quantity: " << record.quantity << endl;  
     cout << "Wholesale cost: " << record.whlCost << endl;  
     cout << "Retail price: " << record.rtlCost << endl;  
     cout << "Date (in 00/00/0000 format): " << record.date << endl;  
    
     if(file.fail())  
     file.clear();  
     file.close();  

 }  

   void chgRec(fstream &file)	

 {  

     fstream inventory ("InventoryFile.txt", ios::out | ios::binary);  
     InventoryItem record;   
     long recNum;  
     cout << "Enter the record number of the item you want to edit: ";  
     cin >> recNum;											

     inventory.seekg(recNum * sizeof(record), ios::beg);  
     inventory.read(reinterpret_cast<char *>(&record),sizeof(record));  

     cout << "Description: " << record.desc << endl;  
     cout << "Quantity: " << record.quantity << endl;  
     cout << "Wholesale cost: " << record.whlCost << endl;  
     cout << "Retail price: " << record.rtlCost << endl;  
     cout << "Date (in 00/00/0000 format): " << record.date << endl;    

    

     inventory.seekp(recNum * sizeof(record), ios::beg);  

   

     inventory.write(reinterpret_cast<char *>(&record),sizeof(record));  

	

     inventory.close();   
}
   int main()  
{ 
    long selection;										 
	int menu();
	selection = menu(); 
    fstream inventory ("Inventory.txt", ios::in | ios::out | ios::binary);  
    InventoryItem record = {" ", 0, 0.0};  
      
    cout << fixed << showpoint << setprecision(2);  
    cout<<"Inventory Managment"<<endl;  

  
    for (int count = 0; count < 5; count++)  

    {  

       inventory.write(reinterpret_cast<char *>(&record),sizeof(record));  

    }  

    inventory.close();  

    inventory.open("Inventory.txt", ios::out | ios::binary);  
	
		 while (selection != 4) 

    {  
       switch(selection)  
        {  

		case 1:													  

            {  
                addRec(inventory);  
                break;  
            }  

        case 2:													   

            {  
			    dispRec(inventory);  
                break;  
            }  

        case 3:													  

            {  
                chgRec(inventory);  
                break;  
            }  

        default:												 

            {  
                cout << "Invalid selection" << endl;  
            }  

            selection = record.menu();  
        }  

    }               
  
    inventory.close();      

    
    return 0;  

 }  

[giblit]

Do you have an executable open already? The error is linking it.

Your error is this:

	int menu();
	selection = menu(); 

In your main function.



Maybe you meant:

InventoryItem test;
selection = test.menu();

Basically you never created the InventoryItem object and you are trying to call the fucntions without the object.

it would be like trying to call the open function from fstream without creating a fstream object

[jlpurnell]

YOU ARE THE GREATEST!

Now I can actually test this and see that nothing happens. LOL!

I guess it cannot read anything in my text file?????

Hmmmmm....

It gives me the error "Inventory Program.exe has stopped working". My console is blank with "Press any key....

[giblit]

It might have to do with this line:

fstream inventory ("Inventory.txt", ios::in | ios::out | ios::binary);

Looks like you just put all the flags you could think of.

You probably want fstream inventory("Inventory.txt" , ios::in); or maybe ios::nocreate also

I'm not sure what you trying to do with that inventory txt read or write?

[jlpurnell]

Line 148 I thought changes the individual record in the file and that I needed the in, out, and binary.

I need to read a file and be able to change it as necessary.

[cire]

Remove lines 28 and 29 from your InventoryItem::menu function.

What would you expect the following to do?

void menu() { menu(); }

int main()
{
    menu() ;
}

[jlpurnell]

THANKS!!