endless loop

[tpinon]

I'm working with binary files for the first time. I'm writing a record to the file and then reading from it. When I get to this function to read and display the records, I get hung on an endless loop. I don't know why because I have the while not at .eof function. Am I not using it right?

void Read(fstream &file, PayInfo &employee)
{
     char answer;
     file.open("employee.dat", ios::in | ios::binary);
     if (!file)
     {
          cout << "Error opening file. Please try again.\n";
     }
     cout << "Here are the contents of the file:\n\n";
     
     file.read(reinterpret_cast<char*>(&employee),sizeof(employee));
     
     while (!file.eof())
     {
           cout << "Full name: "; 
           cout << employee.nameId.fullname;
           cout << "\nEmployee ID#: ";
           cout << employee.nameId.id;
           cout << "\nHourly Rate: $";
           cout << employee.hourlyRate;
           
           file.read(reinterpret_cast<char*>(&employee),sizeof(employee));
     }
     cout << "That's the last record in the file!\n";
     file.close();
}    

[tpinon]

Help please. I'm still stuck with this.

[amchinese]

I think you can use Viscul C++'s debug founction to debug.

I just found a small bug: first, when you can't open the file, you only output a string, but you still read it after that. Also, you need a '\n' befor "Full name".

But I don't know why you are in a endless loop.

Hope you find the solution soon!

[amchinese]

Is your program output all the time or display nothing? Maybe the founction "read" can't read the file.

[tpinon]

No. the program will read and write depending on the option chosen. The problem is that when i enter input using option #2, i don't think it's writing correctly because I can't see the data in the file and I can't read and display it on option #3.

#include <cstdlib>
#include <iostream>
#include <string>
#include <iomanip>
#include <istream>
#include <fstream>

using namespace std;

const int SIZE_A = 25;        
const int SIZE_B = 10;

typedef char String_A[SIZE_A];         
typedef char String_B[SIZE_B];

struct EmpInfo{
               String_A fullname;
               String_B id;
              };
               
struct PayInfo{
               EmpInfo nameId;
               double hourlyRate;
              };

//prototypes below here
void Create(fstream &);
int Menu();   
void Input(fstream &, PayInfo &);
void Read(fstream &, PayInfo &);
void Append(fstream &, PayInfo &);
void Search(fstream &, PayInfo &);
void Delete(fstream &,fstream &, PayInfo &);


int main()
{
    char filename[]= "employees.dat";
    const int HOURS = 80; 
    PayInfo employee;
    int choice, answer;
    
    fstream EmployeeFile, EmployeeFile2;
        
        do
        {
            choice = Menu();
            
            switch(choice)
            {
                 case 1: Create(EmployeeFile);
                         break;
                 case 2: Input(EmployeeFile,employee);
                         break;
                 case 3: Read(EmployeeFile,employee);
                         break;
                 case 4: Append(EmployeeFile,employee);
                         break;
                 case 5: Delete(EmployeeFile,EmployeeFile2,employee);
                         break;
                 case 6: Search(EmployeeFile,employee);
                         break;
                 case 7:
                 case 8:
                 case 9: cout << "\n GOOD BYE." << endl << endl; 
                         break;
                 
            }     
        cout << endl;
        }while (choice != 9);
            
    cout << endl << endl;
    
    system("PAUSE");
    return EXIT_SUCCESS;

}     


void Create(fstream &myFile)
{
     myFile.open("employees.dat", ios::out | ios::binary);
     
     if(myFile.good())
     {
         cout << "File was created successfully.\n"<<endl;
     }
     else
     {
         cout << "File did not open successfully.\n" << endl << endl;
     }
     myFile.clear();
     myFile.close();
}


int Menu()
{
    int mychoice;
    cout << "Choose a menu option: " << endl;
    cout << "1- Create a Binary File\n";
    cout << "2- Populate with a New Record\n";
    cout << "3- Read and Display the Contents of the File\n";
    cout << "4- Append a Record\n";
    cout << "5- Delete a Record\n";
    cout << "6- Search For a Record\n";
    cout << "7- Modify a Record\n";
    cout << "8- Wipe out all records\n";
    cout << "9- Exit\n\n";
    cout << "Enter your choice: ";
    cin >> mychoice;
    return mychoice;
}


void Input(fstream &file, PayInfo &employee)
{               
        file.open("employees.dat", ios::out | ios::binary);        
        if(file.good())
        {
            cout << "File was created successfully.\n"<<endl;
        }
        else
        {
            cout << "File did not open successfully.\n" << endl << endl;
        }
        char answer;  
        cin.ignore(); 
        do
        {             
            cout << "\nEnter the following employee info." << endl << endl;
            cout << "Full name: ";
            cin.getline(employee.nameId.fullname,sizeof(employee.nameId.fullname));
                  
            cout << "Employee ID#: ";
            cin.getline(employee.nameId.id,sizeof(employee.nameId.id));
                            
            do
            {
            cout << "Hourly Rate: $";
            cin >> employee.hourlyRate;
                  
            if (employee.hourlyRate > 0)
                  break;
            else
                  cout << "Invalid pay rate. Must be > $0.00. Try again." << endl;
            } while (1);
            
            file.write((char *)&employee, sizeof(employee));
              
            cout << "\nDo you have another employee to enter? (Y or N) ";
            cin >> answer;
            cin.ignore();
                  
        }while (answer == 'Y' || answer == 'y');
                  cout << endl << endl;
        file.close();
    
}


void Read(fstream &file, PayInfo &employee)
{
     char answer;
     file.open("employee.dat", ios::in | ios::binary);
     if (!file)
     {
          cout << "Error opening file. Please try again.\n";
     }
     cout << "Here is the list of employees:\n\n";
     
     file.read(reinterpret_cast<char*>(&employee),sizeof(employee));
     
     while (!file.eof())
     {
           cout << "\nFull name: "; 
           cout << employee.nameId.fullname;
           cout << "\nEmployee ID#: ";
           cout << employee.nameId.id;
           cout << "\nHourly Rate: $";
           cout << employee.hourlyRate;
           
           file.read(reinterpret_cast<char*>(&employee),sizeof(employee));
     }
     cout << "That's the last record in the file!\n";
     file.clear();
     file.close();
}         

[amchinese]

I think you shoud check something about file stream. I just debuged your program and I found your program said "Error opening file. Please try again"(I used viscul c++ and paused it).

[amchinese]

Also, it display the wrong information when you rerun it.