BMI计算与菜单逻辑

Question

我对编程是完全陌生的，我一直在绞尽脑汁地想着一些我知道的非常基本的东西。我不是一个在网上学习的人，所以事实证明这更加困难。

因此，我需要创建一个C#控制台应用程序，其中有一个菜单，其中有三个选项，其中包括一个“退出”。到目前为止，我只能分别运行选项1和2。当我查看会员比率时，我只能选择选项1。然后，当我尝试将成员和BMI计算的编码放在一起时，我仍然只能运行成员资格！

下面是我的代码：

using System;

namespace BMITEST1MILLION
{
    class Program
    {
        static void Main(string[] args)

        {
            Console.WriteLine("Kiaora! Welcome to City Gym. Please select one of the following options:");
            Console.WriteLine("1.) View Our Membership Rates");
            Console.WriteLine("2.) Calculate My BMI");
            Console.WriteLine("3.) Exit");

            int num = Int32.Parse(Console.ReadLine());

            if (num == 1) ////condition.run if user main menu input is option 1 
            {
                Console.Clear();//clears previous screen

                Console.WriteLine("Which membership type would you like to view?"); //prompting user input
                Console.WriteLine("1.) Basic");
                Console.WriteLine("2.) Regular");
                Console.WriteLine("3.) Premium");


                int num1 = Int32.Parse(Console.ReadLine()); //declare if option 1 chosen
                if (num1 == 1) //condition. run if user input for membership type is 1
                {
                    Console.Clear(); //clears previous screen
                    Console.WriteLine("Our Basic Membership Rate is $10 per week or $40 per month");
                }


                int num2 = Int32.Parse(Console.ReadLine()); //declare if option 2 chosen
                if (num2 == 2) ; //condition. run if user input for membership type is 2
                {
                    Console.Clear(); //clears previous screen
                    Console.WriteLine("Our Regular Membership Rate is $15 per week or $60 per month");
                }

                int num3 = Int32.Parse(Console.ReadLine()); //declare if option 3 chosen
                if (num3 == 3) //condition. run if user input for membership type is 3

                {
                    Console.Clear(); //clears previous screen
                    Console.WriteLine("Our Premium Membership Rate is $20 per week or $80 per month");
                }


                if (num == 2)//condition.run if user main menu input is option 2 (BMI Calcuation)

                    //BMI calculation

                    Console.Write("Enter you height in metres (m):"); //ask user to input their height in metres
                double userHeight = Convert.ToDouble(Console.ReadLine()); // convert string to a double

                Console.Write("Enter you weight in kilograms (kg):"); //ask user to input their wedight in kilograms
                double userWeight = Convert.ToDouble(Console.ReadLine()); // convert string to a double

                double BMI = userWeight / (userHeight * userHeight); //method to calculate BMI based on user input weight and height
                Console.WriteLine("Your BMI is " + Math.Round(BMI, 2)); //print BMI result to screen. Round result to two decimals.

                if (BMI <= 18.5)//condition
                    Console.WriteLine("You are underweight.");

                else
                    if (BMI <= 25)//condition
                    Console.WriteLine("Your weight is normal.");

                else
                    if (BMI <= 30)//condition
                    Console.WriteLine("You are overweight.");

                else //if BMI is greater then 30
                    Console.WriteLine("You are obese.");

                Console.ReadKey();

            }//end of bmi calcuation

        }//main menu
    }//end of class
}//end of namespace

Answer 1

我建议使用do和switch-case：

do {
  switch(option) {
    case 1: //do something
    break;
 
    case 2: //do something
    break;

    case 3: //exit
    break;

    default: // wrong option
    break;
  }
}while(option != 3);

致以问候！

Answer 2

似乎您的主要if语句的结构有点偏离。为了执行备选方案1或备选方案2，它将如下

if(num == 1){
  ...
}
if(num == 2){
  ...
}

但你有

if(num == 1){
  ...
  if(num == 2)
}

也许这就是你把代码放在一起的意思？在这种情况下，由于在if(num == 2)之后没有大括号，所以它只适用于它下面的直线(即打印“输入高度(米)：”)。但是，由于它只在num已经等于1(因为它嵌套在num == 1块中)时才检查此条件，所以该行将永远不会执行，因此它跳过该行并继续执行double userHeight = Convert.ToDouble(Console.ReadLine());。希望这能有所帮助！