اسم الطالب: Ali Alharbi
الرقم الجامعي: 241000861
السؤال الثاني: Budget Management Application
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import 'dart:io';

void main() {
  List<Map<String, double>> incomeList = [];
  List<Map<String, double>> expenseList = [];

  while (true) {
    print("\n=== Budget Management System ===");
    print("1. Add Income");
    print("2. Add Expense");
    print("3. View Summary");
    print("4. Exit");
    stdout.write("Enter your choice: ");
    String? choice = stdin.readLineSync();

    if (choice == "1") {
      stdout.write("Enter income description: ");
      String desc = stdin.readLineSync()!;
      stdout.write("Enter amount: ");
      double? amount = double.tryParse(stdin.readLineSync()!);

      if (amount != null && amount >= 0) {
        incomeList.add({desc: amount});
        print("Income added.");
      } else {
        print("Invalid amount.");
      }
    }

    else if (choice == "2") {
      stdout.write("Enter expense description: ");
      String desc = stdin.readLineSync()!;
      stdout.write("Enter amount: ");
      double? amount = double.tryParse(stdin.readLineSync()!);

      if (amount != null && amount >= 0) {
        expenseList.add({desc: amount});
        print("Expense added.");
      } else {
        print("Invalid amount.");
      }
    }

    else if (choice == "3") {
      double totalIncome = 0;
      double totalExpenses = 0;

      for (var item in incomeList) {
        totalIncome += item.values.first;
      }

      for (var item in expenseList) {
        totalExpenses += item.values.first;
      }

      double net = totalIncome - totalExpenses;

      print("\n=== Summary ===");
      print("Total Income: \$${totalIncome.toStringAsFixed(2)}");
      print("Total Expenses: \$${totalExpenses.toStringAsFixed(2)}");

      if (net >= 0) {
        print("Your net profit is \$${net.toStringAsFixed(2)}");

        double tax = net > 0 ? net * 0.15 : 0;
        print("Tax to be paid: \$${tax.toStringAsFixed(2)}");
      } else {
        print("Your net loss is \$${(-net).toStringAsFixed(2)}");
      }
    }

    else if (choice == "4") {
      print("Exiting program...");
      break;
    }

    else {
      print("Invalid choice.");
    }
  }
}