错误处理

本课属于 Coddy Ruby 学习旅程的“基础知识”单元。第 85 课，共 88 课。

挑战

简单

通过为无效菜单选项添加错误处理，完成每日费用追踪器。

你的程序应当：

初始化一个名为 expenses 的空数组
创建一个 loop do，用于显示菜单并读取用户输入
当用户输入 "1" 时，提示输入费用名称和金额，创建一个包含 :name 和 :amount 键的哈希，将其添加到 expenses 数组中，并输出 Expense added!
当用户输入 "2" 时，显示所有费用；如果没有费用，则显示一条提示信息
当用户输入 "3" 时，计算并显示所有费用的总额和平均值；如果没有费用，则显示一条提示信息
当用户输入 "4" 时，清空数组中的所有费用，并输出 All expenses cleared!
当用户输入 "5" 时，输出 Goodbye! 并退出循环
对于任何其他输入，输出：Invalid option. Please try again.

菜单应与之前完全一致：


--- Expense Tracker ---
1. Add Expense
2. View Expenses
3. Total & Average
4. Clear All
5. Exit
Choose an option:

例如，如果输入依次为 7、abc，然后是 5（两个无效选项，然后退出），输出应为：


--- Expense Tracker ---
1. Add Expense
2. View Expenses
3. Total & Average
4. Clear All
5. Exit
Choose an option: Invalid option. Please try again.

--- Expense Tracker ---
1. Add Expense
2. View Expenses
3. Total & Average
4. Clear All
5. Exit
Choose an option: Invalid option. Please try again.

--- Expense Tracker ---
1. Add Expense
2. View Expenses
3. Total & Average
4. Clear All
5. Exit
Choose an option: Goodbye!

如果输入依次为 1、Coffee、4.5、6、2，然后是 5（添加费用、无效选项、查看、退出），输出应为：


--- Expense Tracker ---
1. Add Expense
2. View Expenses
3. Total & Average
4. Clear All
5. Exit
Choose an option: Expense name: Amount: Expense added!

--- Expense Tracker ---
1. Add Expense
2. View Expenses
3. Total & Average
4. Clear All
5. Exit
Choose an option: Invalid option. Please try again.

--- Expense Tracker ---
1. Add Expense
2. View Expenses
3. Total & Average
4. Clear All
5. Exit
Choose an option: 
--- Your Expenses ---
Coffee: $4.5

--- Expense Tracker ---
1. Add Expense
2. View Expenses
3. Total & Average
4. Clear All
5. Exit
Choose an option: Goodbye!

亲手试试

expenses = []

loop do
  puts "--- Expense Tracker ---"
  puts "1. Add Expense"
  puts "2. View Expenses"
  puts "3. Total & Average"
  puts "4. Clear All"
  puts "5. Exit"
  print "Choose an option: "
  
  choice = gets.chomp
  
  if choice == "1"
    print "Expense name: "
    name = gets.chomp
    print "Amount: "
    amount = gets.chomp.to_f
    expenses << { name: name, amount: amount }
    puts "Expense added!"
  elsif choice == "2"
    if expenses.empty?
      puts "No expenses recorded yet."
    else
      expenses.each do |expense|
        puts "#{expense[:name]}: $#{expense[:amount]}"
      end
    end
  elsif choice == "3"
    if expenses.empty?
      puts "No expenses to calculate."
    else
      total = expenses.sum { |expense| expense[:amount] }
      average = total / expenses.length
      puts "Total: $#{total}"
      puts "Average: $#{average}"
    end
  elsif choice == "4"
    expenses.clear
    puts "All expenses cleared!"
  elsif choice == "5"
    puts "Goodbye!"
    break
  end
  
  puts ""
end