A telephone directory, also known as a telephone book, telephone address book, phone book, or the white/yellow pages, is a listing of telephone subscribers in a geographical area or subscribers to services provided by the organization that publishes the directory. Its purpose is to allow the telephone number of a subscriber identified by name and address to be found.

This is a simple Telephone directory program written using the C++ programming. It uses very simple file handling operations to make up the whole project; these include adding, deleting, searching, listing and modifying records, to or from file.

#include<iostream>
#include<fstream>
#include<iomanip>

using namespace std;



class telephone
{
	char name[20];
	char address[20];
	int ph_no;
public:
	void get(void);
	void show(void);
	int getph_no();
};



void telephone::get(void)
{
	cout << "\nEnter Name: ";
	cin.ignore();
	cin.getline(name, 20);
	cout << "Enter Address: ";
	cin.ignore();
	cin.getline(address, 20);
	cout << "\nEnter Phone Number: ";
	cin >> ph_no;
}


void telephone::show()
{
	cout << "\nName: " << name;
	cout << "\nAddress: " << address;
	cout << "\nPhone Number: " << ph_no;
}

int  telephone::getph_no()
{
	return ph_no;
}


void write_telephone()
{
	telephone tel;
	ofstream outFile;
	outFile.open("telephone.dat", ios::binary | ios::app);
	tel.get();
	outFile.write(reinterpret_cast<char *> (&tel), sizeof(telephone));
	outFile.close();
	cout << "\n\nTelephone Directory Has Been Created...";
	cin.ignore();
	cin.get();
}



void display_all()
{
	telephone tel;
	ifstream inFile;
	inFile.open("telephone.dat", ios::binary);
	if (!inFile)
	{
		cout << "File could not be open !! Press any Key...";
		cin.ignore();
		cin.get();
		return;
	}
	cout << "\n\n\n\t\tDISPLAY ALL RECORD !!!\n\n";
	while (inFile.read(reinterpret_cast<char *> (&tel), sizeof(telephone)))
	{
		tel.show();
		cout << "\n\n====================================\n";
	}
	inFile.close();
	cin.ignore();
	cin.get();
}



void display_sp(int n)
{
	telephone tel;
	ifstream inFile;
	inFile.open("telephone.dat", ios::binary);
	if (!inFile)
	{
		cout << "File could not be open !! Press any Key...";
		cin.ignore();
		cin.get();
		return;
	}
	bool flag = false;
	while (inFile.read(reinterpret_cast<char *> (&tel), sizeof(telephone)))
	{
		if (tel.getph_no() == n)
		{
			tel.show();
			flag = true;
		}
	}
	inFile.close();
	if (flag == false)
		cout << "\n\nrecord not exist";
	cin.ignore();
	cin.get();
}


void modify_telephone(int n)
{
	bool found = false;
	telephone tel;
	fstream File;
	File.open("telephone.dat", ios::binary | ios::in | ios::out);
	if (!File)
	{
		cout << "File could not be open !! Press any Key...";
		cin.ignore();
		cin.get();
		return;
	}
	while (!File.eof() && found == false)
	{

		File.read(reinterpret_cast<char *> (&tel), sizeof(telephone));
		if (tel.getph_no() == n)
		{
			tel.show();
			cout << "\n\nPlease Enter The New Details" << endl;
			tel.get();
			int pos = (-1)*static_cast<int>(sizeof(tel));
			File.seekp(pos, ios::cur);
			File.write(reinterpret_cast<char *> (&tel), sizeof(telephone));
			cout << "\n\n\t Record Updated";
			found = true;
		}
	}
	File.close();
	if (found == false)
		cout << "\n\n Record Not Found ";
	cin.ignore();
	cin.get();
}



void delete_telephone(int n)
{
	telephone tel;
	ifstream inFile;
	inFile.open("telephone.dat", ios::binary);
	if (!inFile)
	{
		cout << "File could not be open !! Press any Key...";
		cin.ignore();
		cin.get();
		return;
	}
	ofstream outFile;
	outFile.open("Temp.dat", ios::out);
	inFile.seekg(0, ios::beg);
	while (inFile.read(reinterpret_cast<char *> (&tel), sizeof(telephone)))
	{
		if (tel.getph_no() != n)
		{
			outFile.write(reinterpret_cast<char *> (&tel), sizeof(telephone));
		}
	}
	outFile.close();
	inFile.close();
	remove("telephone.dat");
	rename("Temp.dat", "telephone.dat");
	cout << "\n\n\tRecord Deleted ..";
	cin.ignore();
	cin.get();
}



int main()
{
	char ch;
	int num;
	cout.setf(ios::fixed | ios::showpoint);
	cout << setprecision(2);
	do
	{
		system("cls");
		cout << "\t\t\t\t**\t**";
		cout << "\t\t\t\t***\t***";
		cout << "\t\t\t\t****\t****";
		cout << "\t\t\t\t*****\t*****";
		cout << "\t\t\t\t******\t******";
		cout << "\t\t\t\t*******\t*******";
		cout << "\t\t\t\t*******\t*******";
		cout << "\t\t\t\t******\t******";
		cout << "\t\t\t\t*****\t*****";
		cout << "\t\t\t\t****\t****";
		cout << "\t\t\t\t***\t***";
		cout << "\t\t\t\t**\t**";
		cout << "\t\t\t\t*\t*";

		cout << "\n\t\t@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@";
		cout << "\n\t\t1. Add Telephone Record";
		cout << "\n\t\t2. Show Records";
		cout << "\n\t\t3. Search Telephone Records";
		cout << "\n\t\t4. Modify Record";
		cout << "\n\t\t5. Delete Record";
		cout << "\n\t\t6. EXIT";
		cout << "\n\t\t@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@";
		cout << "\n\t\tPlease Enter Your Choice (1-6): ";
		cin >> ch;
		system("cls");
		switch (ch)
		{
		case '1':	write_telephone(); break;
		case '2':	display_all(); break;
		case '3':	cout << "\n\tPlease Enter Phone Number: "; cin >> num;
			display_sp(num); break;
		case '4':	cout << "\n\tPlease Enter Phone Number: "; cin >> num;
			modify_telephone(num); break;
		case '5':	cout << "\n\tPlease Enter Phone Number: "; cin >> num;
			delete_telephone(num); break;
		case '6':	exit(0);
		default:	cout << "\a";

		}
	} while (ch != '7');

	return 0;
}