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UserLogin.cpp

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+#include <iostream>
+#include <limits>
+#include <fstream>
+#include "functions.h"
+using namespace std;
+
+int main() {
+ int choice;
+ cout << "1. Register\n2. Login\n3. Update Password\n4. Delete File\n5. Exit" << endl << "Enter your choice: ";
+
+ while (true) {
+ try {
+ cin >> choice;
+
+ if (cin.fail()) {
+ cin.clear();
+ cin.ignore(numeric_limits<streamsize>::max(), '\n');
+ throw invalid_argument("Invalid choice. Please enter a valid number.");
+ }
+
+ switch (choice) {
+ case 1:
+ registerUser();
+ break;
+ case 2:
+ loginUser();
+ break;
+ case 3:
+ updatePassword();
+ break;
+ case 4:
+ deleteFile();
+ break;
+ case 5:
+ cout << "Thank you for using the program. Goodbye!" << endl;
+ return 0;
+ default:
+ throw invalid_argument("Invalid choice. Please enter a valid number.");
+ }
+ } catch (const invalid_argument& e) {
+ cout << e.what() << endl;
+ }
+
+ cout << "1. Register\n2. Login\n3. Update Password\n4. Delete File\n5. Exit" << endl << "Enter your choice: ";
+ }
+
+ cout << "Thank you for using the program. Goodbye!" << endl;
+ return 0;
+}

functions.h

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+// functions.h
+#ifndef FUNCTIONS_H
+#define FUNCTIONS_H
+
+#include <iostream>
+#include <fstream>
+#include <string>
+
+// Function prototypes
+std::string encrypt(const std::string& text, char key);
+bool isLoggedIn(const std::string& username, const std::string& password, const std::string& filename);
+void registerUser();
+void loginUser();
+void updatePassword();
+void deleteFile();
+
+// Function to encrypt a string using a simple XOR technique
+std::string encrypt(const std::string& text, char key) {
+ std::string result = "";
+
+ // Iterate through each character in the text and apply XOR with the key
+ for (const auto& ch : text) {
+ result += ch ^ key;
+ }
+ return result;
+}
+
+// Function to check if a user is registered and their password is correct
+bool isLoggedIn(const std::string& username, const std::string& password, const std::string& filename) {
+ std::string encryptedUsername, encryptedPassword, un, pw;
+ const char encryptionKey = 'K'; // Set the encryption key
+
+ // Encrypt the username and password using the encryption key
+ encryptedUsername = encrypt(username, encryptionKey);
+ encryptedPassword = encrypt(password, encryptionKey);
+
+ // Read the registered user data from the file
+ std::ifstream infile(filename);
+ if (infile.is_open()) {
+ // Loop through each line in the file and compare the encrypted data
+ while (std::getline(infile, un) && std::getline(infile, pw)) {
+ if (un == encryptedUsername && pw == encryptedPassword) {
+ infile.close();
+ return true;
+ }
+ }
+ infile.close();
+ }
+ return false;
+}
+
+// Function for user registration
+void registerUser() {
+ std::string username, password, filename;
+
+ // Check if the file already exists and prompt for a unique filename
+ bool uniqueFile = false;
+ while (!uniqueFile) {
+ std::cout << "Enter a filename for your account: ";
+ std::cin >> filename;
+ std::ifstream infile(filename);
+ if (!infile.good()) {
+ uniqueFile = true;
+ } else {
+ std::cout << "Error: Filename already exists. Please choose another filename." << std::endl;
+ }
+ infile.close();
+ }
+
+ std::cout << "Enter a username: ";
+ std::cin >> username;
+ std::cout << "Enter a password: ";
+ std::cin >> password;
+
+ // Encrypt the username and password using the encryption key
+ const char encryptionKey = 'K';
+ std::string encryptedUsername = encrypt(username, encryptionKey);
+ std::string encryptedPassword = encrypt(password, encryptionKey);
+
+ // Save the encrypted registration details to a text file
+ std::ofstream outfile(filename, std::ios::app);
+ if (outfile.is_open()) {
+ outfile << encryptedUsername << std::endl << encryptedPassword << std::endl;
+ outfile.close();
+ std::cout << "Registration successful." << std::endl;
+ } else {
+ std::cout << "Error: Unable to open file." << std::endl;
+ }
+}
+
+// Function for user login
+void loginUser() {
+ std::string username, password, filename;
+ std::cout << "Enter the filename of your account: ";
+ std::cin >> filename;
+
+ // Check if the file exists
+ std::ifstream infile(filename);
+ if (!infile.is_open()) {
+ std::cout << "Error: File not found. Please make sure you entered the correct filename." << std::endl;
+ } else {
+ infile.close();
+ std::cout << "Enter your username: ";
+ std::cin >> username;
+ std::cout << "Enter your password: ";
+ std::cin >> password;
+
+ // Check if the user is registered and the password is correct
+ if (isLoggedIn(username, password, filename)) {
+ std::cout << "Login successful." << std::endl;
+ } else {
+ std::cout << "Incorrect username or password." << std::endl;
+ }
+ }
+}
+
+// Function for updating password
+void updatePassword() {
+ std::string username, oldPassword, newPassword, filename;
+ std::cout << "Enter the filename for your account: ";
+ std::cin >> filename;
+
+ // Check if the file exists
+ std::ifstream infile(filename);
+ if (!infile.is_open()) {
+ std::cout << "Error: File not found. Please make sure you entered the correct filename." << std::endl;
+ } else {
+ infile.close();
+ std::cout << "Enter your username: ";
+ std::cin >> username;
+ std::cout << "Enter your current password: ";
+ std::cin >> oldPassword;
+
+ // Check if the user is registered and the password is correct
+ if (isLoggedIn(username, oldPassword, filename)) {
+ std::cout << "Enter your new password: ";
+ std::cin >> newPassword;
+
+ // Update the password in the file
+ std::ofstream outfile(filename);
+ if (outfile.is_open()) {
+ outfile << encrypt(username, 'K') << std::endl << encrypt(newPassword, 'K') << std::endl;
+ outfile.close();
+ std::cout << "Successfully changed password." << std::endl;
+ } else {
+ std::cout << "Error: Unable to open file." << std::endl;
+ }
+ } else {
+ std::cout << "Incorrect username or password." << std::endl;
+ }
+ }
+}
+
+// Function for deleting File
+void deleteFile() {
+ std::string username, password, filename;
+ std::cout << "Enter the filename for your account: ";
+ std::cin >> filename;
+
+ // Check if the file exists
+ std::ifstream infile(filename);
+ if (!infile.is_open()) {
+ std::cout << "Error: File not found. Please make sure you entered the correct filename." << std::endl;
+ } else {
+ infile.close();
+ std::cout << "Enter your username: ";
+ std::cin >> username;
+ std::cout << "Enter your password: ";
+ std::cin >> password;
+
+ // Check if the user is registered and the password is correct
+ if (isLoggedIn(username, password, filename)) {
+ // Delete the file
+ if (remove(filename.c_str()) == 0) {
+ std::cout << "Successfully deleted your account." << std::endl;
+ } else {
+ std::cout << "Error: Unable to delete file." << std::endl;
+ }
+ } else {
+ std::cout << "Incorrect username or password." << std::endl;
+ }
+ }
+}
+
+#endif