project12.cpp

/*
 * April 28, 2020
 * Mizuki Hashimoto
 * Project 12
 * This program creates an empty random access file, adds, updates, deletes, and prints (displays)
 * the data in/from the file.
 */

#include <iostream>
#include <iomanip>
#include <fstream>
#include "Person.h"

using namespace std;

char enterChoice();
void createTextFile( fstream& );
void updateRecord( fstream& );
void newRecord( fstream& );
void deleteRecord( fstream& );
void outputLine( ostream&, const Person & );
int getidNumber( const char * const );


int main() {
  char ans;
  cout << "Do you want to create an empty file (y/n)? ";
  cin >> ans;
  if (ans=='y' || ans=='Y') {
    //create nameage.dat to hold 100 possible person objects
    ofstream outPerson("nameage.dat", ios::out | ios::binary);

    // exit program if ofstream could not open file
    if ( !outPerson ) {
      cerr << "File could not be opened." << endl;
      exit(1);
    }

    Person blankPerson; // constructor zeros out each data member

    // output 100 blank records to file
    for (int i = 0; i < 100; ++i) {
      outPerson.write(reinterpret_cast< const char * >(&blankPerson), sizeof(Person));
    }

    outPerson.close();
  }

  fstream inOutPerson("nameage.dat", ios::in | ios::out | ios::binary);

  char choice; // store user choice

  while ((choice = enterChoice()) != 'E' && choice != 'e') {
    switch (choice) {
      case 'P':
      case 'p':// print/display data
        createTextFile(inOutPerson);
        break;
      case 'U':
      case 'u':// update record
        updateRecord(inOutPerson);
        break;
      case 'A':
      case 'a':// add a new record
        newRecord(inOutPerson);
        break;
      case 'D':
      case 'd':// delete existing record
        deleteRecord(inOutPerson);
        break;
      default: // display error if user does not select valid choice
        cerr << "Incorrect choice" << endl;
        break;
    }

    inOutPerson.clear(); // reset
  }
}

// enable user to input menu choice
char enterChoice() {
  // display available options
  cout << "\nEnter your choice" << endl
       << "P - Print/Display a list of people" << endl
       << "U - Update a person" << endl
       << "A - Add a new person" << endl
       << "D - Delete a person" << endl
       << "E - End program\n> ";

  char menuChoice;
  cin >> menuChoice; // input menu selection from user
  return menuChoice;
}

// create formatted text file for printing (uses nameage.dat as input)
void createTextFile(fstream &readFromFile) {
  // create text file
  ofstream outPrintFile("print.txt", ios::out);

  // exit program if ofstream cannot create file
  if (!outPrintFile) {
    cerr << "File could not be created." << endl;
    exit( 1 );
  }

  //display header information to file and to cout
  cout << left << setw(11) << "ID Number" << setw(16) << "Last Name" << setw(11) << "First Name"
    << setw(10) << right << "Age" << endl;
  outPrintFile << left << setw(11) << "ID Number" << setw(16) << "Last Name" << setw(11) << "First Name"
    << setw(10) << right << "Age" << endl;

  // set file-position pointer to beginning of readFromFile
  readFromFile.seekg(0);

  // read first record from record file
  Person person;
  readFromFile.read(reinterpret_cast< char * >(&person), sizeof(Person));

  // copy all records from record file into text file
  while (!readFromFile.eof()) {
    // write single record to text file
    if (person.getId() != 0) {
      //write to file
      outputLine(outPrintFile, person);
      //write to cout
      outputLine(cout, person);
    }

    // read next record from record file
    readFromFile.read(reinterpret_cast< char * >(&person), sizeof(Person));
  }
}

// update age in record
void updateRecord( fstream &updateFile ) {
  // obtain number of idNumber to update
  int idNumber = getidNumber("Enter Id Number to update");

  // move file-position pointer to correct record in file
  updateFile.seekg( (idNumber - 1) * sizeof(Person));

  // read first record from file
  Person person;
  updateFile.read(reinterpret_cast< char * >(&person), sizeof(Person));

  //update record
  if(person.getId() != 0) {
    outputLine(cout, person); // display the record

    // ask user which information to update
    cout << "Do you want to update name (n) or age (a)?" << endl;
    char nora; // n or a
    cin >> nora;

    if (nora == 'n') {
      // request user to update name
      cout << "\nEnter new name:" << endl;
      string lastName;
      string firstName;
      cin >> lastName;
      cin >> firstName;

      // update name
      person.setLastName(lastName);
      person.setFirstName(firstName);
    }
    else if (nora == 'a') {
      // request user to update age
      cout << "\nEnter new age:" << endl;
      int age;
      cin >> age;

      // update age
      person.setAge(age);
    }

    // move file-position pointer to correct record in file
    updateFile.seekp( (idNumber - 1) * sizeof(Person));

    // write updated record over old record in file
    updateFile.write(reinterpret_cast< const char * >(&person), sizeof(Person));
  }
  else // display error if idNumber does not exist
  {
    cerr << "Id # " << idNumber << " has no information." << endl;
  }
}

// create and insert record
void newRecord( fstream &insertInFile ) {
  // obtain number of idNumber to create
  int idNumber = getidNumber("Enter new Id Number");

  // move file-position pointer to correct record in file
  insertInFile.seekg( ( idNumber - 1) * sizeof(Person));

  // read record from file
  Person person;
  insertInFile.read(reinterpret_cast< char * >(&person), sizeof(Person));

  // create record, if record does not previously exist
  if ( person.getId() == 0 ) {
    string lastName;
    string firstName;
    int age;

    // user enters last name, first name and age
    cout << "Enter lastname, firstname, age\n> ";
    cin >> setw( 15 ) >> lastName;
    cin >> setw( 10 ) >> firstName;
    cin >> age;

    // use values to populate record
    person.setId(idNumber);
    person.setLastName(lastName);
    person.setFirstName(firstName);
    person.setAge(age);

    // move file-position pointer to correct record in file
    insertInFile.seekp( ( idNumber - 1) * sizeof(Person));

    // insert record in file
    insertInFile.write(reinterpret_cast< const char * >(&person), sizeof(Person));

    //display header information to cout
    cout << left << setw(11) << "ID Number" << setw(16) << "Last Name" << setw(11) << "First Name"
         << setw(10) << right << "Age" << endl;

    //write to cout
    outputLine(cout, person);
  }
  else // display error if idNumber already exists
  {
    cerr << "Id # " << idNumber << " already contains information." << endl;
  }
}

// delete an existing record
void deleteRecord( fstream &deleteFromFile ) {
  // obtain number of idNumber to delete
  int idNumber;
  idNumber = getidNumber("Enter Id Number to delete");

  // move file-position pointer to correct record in file
  deleteFromFile.seekg( ( idNumber - 1) * sizeof(Person));

  // read record from file
  Person person;
  deleteFromFile.read(reinterpret_cast< char * >(&person), sizeof(Person));

  // delete record, if record exists in file
  if(person.getId() != 0) {
    Person blankPerson; // create blank record

    // move file-position pointer to correct record in file
    deleteFromFile.seekp( (idNumber - 1) * sizeof(Person));

    // replace existing record with blank record
    deleteFromFile.write(reinterpret_cast< const char * >(&blankPerson), sizeof(Person));

    cout << "Id #" << idNumber << " deleted.\n";
  }
  else // display error if idNumber does not exist
  {
    cerr << "Id #" << idNumber << " is empty" << endl;
  }
}

// display single record
void outputLine( ostream &output, const Person &record ) {
  output << left << setw( 11 ) << record.getId()
         << setw( 16 ) << record.getLastName()
         << setw( 11 ) << record.getFirstName()
         << setw( 10 ) << right << record.getAge() << endl;
}

// obtain idNumber-number value from user
int getidNumber(const char * const prompt) {
  int idNumber;

  //obtain idNumber-number value
  do {
    cout << prompt << " (1-100): ";
    cin >> idNumber;
  } while (idNumber < 1 || idNumber > 100);

  return idNumber;
}

/*
-------------------------output-------------------------
Do you want to create an empty file (y/n)? y

Enter your choice
P - Print/Display a list of people
U - Update a person
A - Add a new person
D - Delete a person
E - End program
> A
Enter new Id Number (1-100): 3
Enter lastname, firstname, age
> xxx
bbbb
33
ID Number  Last Name       First Name        Age
3          xxx             bbbb               33

Enter your choice
P - Print/Display a list of people
U - Update a person
A - Add a new person
D - Delete a person
E - End program
> A
Enter new Id Number (1-100): 5
Enter lastname, firstname, age
> uuu
eee
55
ID Number  Last Name       First Name        Age
5          uuu             eee                55

Enter your choice
P - Print/Display a list of people
U - Update a person
A - Add a new person
D - Delete a person
E - End program
> P
ID Number  Last Name       First Name        Age
3          xxx             bbbb               33
5          uuu             eee                55

Enter your choice
P - Print/Display a list of people
U - Update a person
A - Add a new person
D - Delete a person
E - End program
> D
Enter Id Number to delete (1-100): 2

Id #2 is empty
Enter your choice
P - Print/Display a list of people
U - Update a person
A - Add a new person
D - Delete a person
E - End program
> D
Enter Id Number to delete (1-100): 5
Id #5 deleted.

Enter your choice
P - Print/Display a list of people
U - Update a person
A - Add a new person
D - Delete a person
E - End program
> P
ID Number  Last Name       First Name        Age
3          xxx             bbbb               33

Enter your choice
P - Print/Display a list of people
U - Update a person
A - Add a new person
D - Delete a person
E - End program
> U
Enter Id Number to update (1-100): 3
3          xxx             bbbb               33
Do you want to update name (n) or age (a)?
a

Enter new age:
34

Enter your choice
P - Print/Display a list of people
U - Update a person
A - Add a new person
D - Delete a person
E - End program
> P
ID Number  Last Name       First Name        Age
3          xxx             bbbb               34

Enter your choice
P - Print/Display a list of people
U - Update a person
A - Add a new person
D - Delete a person
E - End program
> E

Process finished with exit code 0

Do you want to create an empty file (y/n)? n

Enter your choice
P - Print/Display a list of people
U - Update a person
A - Add a new person
D - Delete a person
E - End program
> P
ID Number  Last Name       First Name        Age
3          xxx             bbbb               34

Enter your choice
P - Print/Display a list of people
U - Update a person
A - Add a new person
D - Delete a person
E - End program
> E

Process finished with exit code 0
 */