{
 
  // Open file
  ifstream phonebook;
 
  string nameToLookUp;
 
  string firstName;
  string lastName;
  string phoneNumber;
  char   runAgain;
 
  firstName="";
  lastName="";
 
  runAgain = 'y';
 
    phonebook.open("Phone.dat");
    if ( !phonebook )      { //If input doesn't open...
      //no
      cout << "Can't open the phonebook file." << endl;
      system("PAUSE");    
      return 1;            //terminate the program
    }
 
 
  while (runAgain=='y'||runAgain=='Y') {
 
    phonebook.close();    
    phonebook.open("Phone.dat");
    cout<<"What Name to look up? ";
    cin >> nameToLookUp; 
    while (firstName!=nameToLookUp&&lastName!=nameToLookUp&&!phonebook.eof()) { 
          phonebook >> firstName >> lastName >> phoneNumber;
    }        
 
    if (!phonebook.eof())
        cout << phoneNumber << endl;
    else
        cout << "Could not find the phone number" << endl;
 
    cout << "Run again? ";
    cin >> runAgain;
  }  
 
  phonebook.close();
  system("pause");
  return (0);  
}

#include <cstdlib>
#include <fstream>
#include <iostream>
#include <string>
#include <vector>
 
using namespace std;
 
int main()
{
  cout<<"An empty string or EOF will stop the program"<<endl;
 
  for ( ; ; ) {
    string name;
 
    cout<<"Enter a name to search for: ";
    if ( !getline ( cin, name ) || name.empty() )
      break;
 
    ifstream phonebook ( "phone.dat" );
 
    if ( !phonebook ) {
      cerr<<"Error opening file"<<endl;
      return EXIT_FAILURE;
    }
 
    vector<string> lines;
    string line;
 
    while ( getline ( phonebook, line ) ) {
      if ( line.find ( name ) )
        lines.push_back ( line );
    }
 
    if ( lines.empty() )
      cout<<"No records found"<<endl;
    else if ( lines.size() == 1 )
      cout<<"One record found"<<endl;
    else
      cout<<"Multiple records found"<<endl;
 
    for ( vector<string>::size_type i = 0; i < lines.size(); i++ )
      cout<< lines[i] <<endl;
  }
 
  return EXIT_SUCCESS;
}