MyPhonebook.cpp

#include <iostream>
#include <fstream>
#include <string>
#include <vector>
#include <sstream>

using namespace std;

void writeEntry(const string& filename, const string& name, const string& phone, int entryNumber) {
    ofstream outFile(filename.c_str(), ios::app);
    if (!outFile) {
        cerr << "Error opening file for writing." << endl;
        return;
    }
    outFile << entryNumber << ". " << name << ": " << phone << endl;
    outFile.close();
}

void deleteEntry(const string& filename, int entryNumber) {
    ifstream inFile(filename.c_str());
    ofstream tempFile("temp.txt");

    if (!inFile || !tempFile) {
        cerr << "Error opening file for reading or writing." << endl;
        return;
    }

    string line;
    while (getline(inFile, line)) {
        // Extract the number from the start of the line
        istringstream lineStream(line);
        int number;
        char dot;
        lineStream >> number >> dot;

        if (number != entryNumber) {
            tempFile << line << endl;
        }
    }

    inFile.close();
    tempFile.close();

    remove(filename.c_str());
    rename("temp.txt", filename.c_str());

    cout << "Contact successfully deleted." << endl;
}

void displayEntries(const string& filename) {
    ifstream inFile(filename.c_str());
    if (!inFile) {
        cerr << "Error opening file for reading." << endl;
        return;
    }

    cout << "\n";  // Output vertical tab before the entries
    cout << "\t";

    string line;
    while (getline(inFile, line)) {
        cout << line << endl;
    }

    inFile.close();
}

int main() {
    string filename = "data.txt";
    string dataToWrite_Name;
    string dataToWrite_Phone;
    int entryNumber = 1;  // To keep track of the entry number

    cout << "Welcome to MyPhoneBook!" << endl;

    while (true) {
        cout << "\n"<<"\t"<<"1. Add entry" << endl;
        cout << "\t2. Delete entry" << endl;
        cout << "\t3. Display entries" << endl;
        cout << "\t4. Clear all data" << endl;
        cout << "\t5. Exit" << endl;
        cout << "\tChoose an option: ";
        int choice;
        cin >> choice;
        cin.ignore();  // Ignore newline character left in the buffer

        switch (choice) {
            case 1:
                // Get the name and phone number
                cout << "\tPlease enter Name and Phone number (Enter -1 to end entry)" << endl;
                cout << "\tName: ";
                getline(cin, dataToWrite_Name);

                if (dataToWrite_Name == "-1") {
                    continue;
                }

                cout << "\tPhone: ";
                getline(cin, dataToWrite_Phone);

                if (dataToWrite_Phone == "-1") {
                    continue;
                }

                // Write entry to file
                writeEntry(filename, dataToWrite_Name, dataToWrite_Phone, entryNumber);
                entryNumber++;  // Increment the entry number for the next entry
                break;

            case 2:
                {
                    // Display entries and ask for the number to delete
                    displayEntries(filename);
                    cout << "\tEnter the number of the contact to delete: ";
                    int numberToDelete;
                    cin >> numberToDelete;
                    cin.ignore();  // Ignore newline character left in the buffer
                    deleteEntry(filename, numberToDelete);
                }
                break;

            case 3:
            	
                displayEntries(filename);
                break;

            case 4:
                {
                    ofstream outFile(filename.c_str(), ios::trunc);
                    if (!outFile) {
                        cerr << "\tError opening file for clearing." << endl;
                        return 1;
                    }
                    outFile.close();
                    cout << "\tAll data has been cleared." << endl;
                }
                break;

            case 5:
                return 0;

            default:
                cout << "\tInvalid option, please try again." << endl;
        }
    }

    return 0;
}