所以我制作了一个程序（c#）来收集变量并对其进行计算。
如何防止菜单选项导致错误？IE 当尝试对一个空列表进行平均计算时，它会破坏程序。
我应该用 list.length > 1 做一个基本的 if 语句吗？
任何人都可以评论这在实用性等方面的外观
using System;
using System.Collections.Generic;
using System.Linq;
namespace exercise2._2
{
public class Program
{
static List<int> list = new List<int>(); //Publicly accessable list declaration for integer collection
static void Main(string[] args)
{
Console.WriteLine("Hello and Welcome. \n Press Any Key To Enter the Menu "); //Output - Welcome and Menu display
Console.ReadKey();
menu();
}
public static void menu()
{
{ start: //Label for validation and re-entering menu
Console.Clear(); //Keeps the menu in place and displays options
Console.WriteLine("Please Select an Option:");
Console.WriteLine("Press 1 To Enter Numerical Values ");
Console.WriteLine("Press 2 To Peform Sum Calculation");
Console.WriteLine("Press 3 To Perform Average Calculation");
Console.WriteLine("Press 4 To Perform Median Calculation");
Console.WriteLine(" ~~ Press 5 To Quit ~~ ");
Console.Write("\r\nSelect an Option: ");
string ans = Console.ReadLine(); //Declaration for menu selection
int ans1;
if (!int.TryParse(ans, out ans1) ) //Data Validation for menu selection (non numerical)
{
Console.WriteLine( "~~Incorrect Data Input~~ \n Press Any Key To Continue" );
Console.ReadKey();
goto start;
}
if (ans1 == 1) //Option 1 of the menu
{
list.Clear(); //Clear List Method
Collection(); //Populate List Method
}
else if (ans1 == 2) //Option 2 - Sum
{
double total = list.Sum(); //Variable declaration for the sum of the list elements
Console.WriteLine("The Sum of the numbers is " + total); //Display for variable
Console.WriteLine("~~Press Any Key to return to the menu~~");
Console.ReadKey();
goto start; //Return to menu
}
else if (ans1 == 3) //Option 3 - Average
{
double average = list.Average(); //Variable declaration for the average of the list elements
Console.WriteLine("The Average is "+average); //Display for variable
Console.WriteLine("~~Press Any Key to return to the menu~~");
Console.ReadKey();
goto start; //Return to menu
}
else if (ans1 == 4) //Option 4 - Median
{
double median; //Variable declaration
list.Sort(); //Sorting list numerically
int length = list.Count(); //Variable declaration for list length
int halfLength = list.Count()/2; //Variable declaration for half list length
if (length % 2 == 0) //if statement halfing the length and execute code depending on a remainder
{
double med1 = list.ElementAt(halfLength) + list.ElementAt(halfLength - 1);//variable collecting and adding 2 middle values if list legnth is odd
median = med1 / 2; //Dividing by 2 for median
}
else
{
median = list.ElementAt(halfLength); //Listing middle value if list length is even
}
Console.WriteLine("The Median is " + median); //Output median value
Console.WriteLine("~~Press Any Key To Return To The Menu~~");
Console.ReadKey();
goto start;
}
else if (ans1 == 5) //Menu option 5 - Quit
{
Console.WriteLine("~~Press Any Key To Exit~~");
Console.ReadKey();
}
else //Output if a number is entered that is not in the menu
{
Console.WriteLine(" --!! Please Make A Selection From The Menu !!-- \n Press Any Key To Continue ");
Console.ReadKey();
goto start;
}
}
}
static void Collection() //Method for collecting List elements
{
string input; //Variable declaration
int inputV;
int i;
Console.WriteLine("Please Enter Values, if you wish to stop enter 0");
for (i = 1; i != 0; i++) //For loop that runs until 0 is entered
{
retry: //start point for data validation
Console.WriteLine("Please enter value " + i); //Output to collect element and inform how many have been entered
input = Console.ReadLine();
if (!int.TryParse(input, out inputV)) //Data validation for list elements
{
Console.WriteLine("Incorrect Data Input");
goto retry;
}
if (inputV == 0) //Instructing for loop what to do when 0 is entered
{
menu(); //Method call for menu
}
list.Add(inputV); //add entries to the list //For loop result. List population
}
}
}
}