Update file_handler.cpp

SimpleDigitalWalletSystem/file_handler.cpp

@@ -2,13 +2,39 @@
 #include <fstream>
 
 bool FileHandler::saveUserData(const std::vector<User>& users, const std::string& filename) {
+  void saveUserData() {
+    std::ofstream file("users.txt");
+    if (file.is_open()) {
+        for (const auto& user : users) {
+            file << user.username << " " << user.password << " " << user.balance << std::endl;
+        }
+        file.close();
+        std::cout << "User data saved successfully." << std::endl;
+    } else {
+        std::cerr << "Error: Unable to open file for writing." << std::endl;
+    }
+}
 
 
 
-};
 
-bool FileHandler::loadUserData(std::vector<User>& users, const std::string& filename) {
 
+};
 
+bool FileHandler::loadUserData(std::vector<User>& users, const std::string& filename) {
 
-};
+void loadUserData() {
+    std::ifstream file("users.txt");
+    if (file.is_open()) {
+        std::string username, password;
+        double balance;
+        while (file >> username >> password >> balance) {
+            users.push_back({username, password, balance});
+        }
+        file.close();
+        std::cout << "User data loaded successfully." << std::endl;
+    } else {
+        std::cerr << "Error: Unable to open file for reading." << std::endl;
+    }
+}
+};