添加开支

本课属于 Coddy Swift 学习旅程的“基础知识”单元。第 79 课，共 86 课。

挑战

简单

在上一课中，你创建了一个菜单循环，用户输入 "5" 时循环会退出。现在，为选项 "1" 实现“添加支出”功能。

修改代码以处理选项 "1"：

用户输入 "1" 时，打印 Enter expense amount:
使用 readLine() 读取支出金额
将输入转换为 Double，并将其追加到 expenses 数组中
成功添加支出后，打印 Expense added!
选项 "2"、"3" 和 "4" 仍应打印 Coming soon...
选项 "5" 仍应打印 Goodbye! 并退出

预期行为：

输入 "1" 时，提示输入支出金额，将金额添加到数组中，并显示确认信息
每次操作后，菜单都会继续显示，直到输入 "5"

交互示例：

1. Add expense
2. View all expenses
3. Show total and average
4. Clear all expenses
5. Exit
1
Enter expense amount:
25.50
Expense added!
1. Add expense
2. View all expenses
3. Show total and average
4. Clear all expenses
5. Exit
1
Enter expense amount:
10.00
Expense added!
1. Add expense
2. View all expenses
3. Show total and average
4. Clear all expenses
5. Exit
5
Goodbye!

亲手试试

// Daily Expense Tracker - Menu Display

var expenses: [Double] = []

while true {
    // TODO: Write your code below to print the menu options
    // Each option should be on its own line with the format: "number. option text"
    print("1. Add expense")
    print("2. View all expenses")
    print("3. Show total and average")
    print("4. Clear all expenses")
    print("5. Exit")
    
    let choice = readLine()
    
    if choice == "5" {
        print("Goodbye!")
        break
    } else {
        print("Coming soon...")
    }
}

基础知识中的所有课

自己练习： Swift 在线编辑器