仅将数字添加到数组C＃验证数字

Question

I'm taking a C# class this semester and it has been quite fun so far. I have an assignment where I need to do several things with an array: add numbers in the array, see the numbers entered in the array, find a number in the array, sort the numbers in the array, create statistics based on the array numbers, and finally exit the application.

So far I have been having a little bit of an issue with adding numbers to the array while making sure that the data entered is only numbers. I think I am about to figure it out, but help is always appreciated. And, does my findData() method look ok?

Thank you again for your time in reading this question!

class Program
{

    static char myChoice = Console.ReadKey().KeyChar;
    static double[] myArray = new double[100];
    static void Main(string[] args)
    {



        while (true)
        {

            Console.WriteLine("Welcome to Lab 2");
            Console.WriteLine();
            Console.WriteLine("Main Menu");
            Console.WriteLine("1- Add new data");
            Console.WriteLine("2- See all data");
            Console.WriteLine("3- Find a number");
            Console.WriteLine("4- Sort the data");
            Console.WriteLine("5- Create statistics");
            Console.WriteLine("6- Exit Program");


            switch (myChoice)
            {
                case '1':
                    Console.WriteLine("1- Add new data");
                    addData();
                    break;

                case '2':
                    Console.WriteLine("2- See all data");
                    seeData();
                    break;

                case '3':
                    Console.WriteLine("3- Find a number");
                    findData();
                    break;

                case '4':
                    Console.WriteLine("4- Sort the data");
                    sortData();
                    break;

                case '5':
                    Console.WriteLine("5- Create statistics");
                    createData();
                    break;

                case '6':
                    Console.WriteLine();
                    exitProgram();
                    break;

            }
        }
    }

    //This method will add numbers to the array
    public static void addData()
    {
        bool isNumber = false;
        double number;
        double temp;

        for (int i = 0; i < myArray.Length; i++)
        {
            Console.WriteLine("Enter a number you would like to add");

            myArray[i] = Convert.ToDouble(Console.ReadLine());
            temp = myArray[i];

            if (!Double.TryParse(temp, out number))
            {
                Console.WriteLine("Invalid input. Please enter a valid number")
            }

            else
            {

            }
        }
    }

    //This method will see the numbers entered in the array
    public static void seeData()
    {
        foreach (var item in myArray)
        {
            Console.WriteLine(item.ToString());
        }
    }

    //This method will find a specific number within the array and check if it has already been entered
    public static void findData()
    {

        Console.WriteLine("Find a number");
        string myChoice = Console.ReadLine();
        double number;
        bool isNumber = Double.TryParse(myChoice, out number);

        {

        }

    }

    //This method will sort the array ascending to descending
    public static void sortData()
    {
        Console.WriteLine("The array has been sorted in ascending order");
        Array.Sort(myArray);
        Console.WriteLine("The array has been sorted in descending order");
        Array.Reverse(myArray);
    }

    //This method will create statistics based on the numbers in the array
    public static void createData()
    {

        //Sum
        double sum = myArray.Sum();
        Console.WriteLine("The total sum of the array is: " + sum);

        //Average
        double average = sum / myArray.Length;
        Console.WriteLine("The average number of the array is: " + average);

        //Maximum
        double maximum = myArray.Max();
        Console.WriteLine("The maximum value in the array is: " + maximum);

        //Minimum
        double minimum = myArray.Min();
        Console.WriteLine("The minimum value in the array is: " + minimum);

        //Mean
        double mean = sum / myArray.Length;
        Console.WriteLine("The mean average of the array is: " + mean);
    }

    //This method will exit the program
    public static void exitProgram()
    {
        Environment.Exit(0);
    }
}

}

Answer 1

does my findData() method look ok?

Your findData() method does acutally nothing.

Here is one approach

public static void findData()
{
    Console.WriteLine("Find a number");
    string myChoice = Console.ReadLine();
    double number = -1;  

    if(!Double.TryParse(myChoice, out number))
    {
        Console.WriteLine("Invalid number");
    }
    else if (Array.IndexOf<double>(myArray, number) == -1)
    {
        Console.WriteLine("Number does not exist");
    }
    else
    {
        Console.WriteLine("Number does exist");
    }
}

Answer 2

This should solve your add problem

  public static void addData()
            {
                for (int i = 0; i < myArray.Length; i++)
                {
                    bool success = false;
                    while (!success)
                    {
                        Console.WriteLine("Enter a number you would like to add");
                        string input = Console.ReadLine();
                        double number;
                        if (Double.TryParse(input, out number))
                        {
                            success = true;
                            myArray[i] = number;
                        }

                        else
                        {
                            Console.WriteLine("Invalid input. Please enter a valid number")
                        }
                    }
                }
            }

Answer 3

Your addData method doesn't make much sense: you first insert a double value into array and then you check if that value is a double (and it certainly is, because the array is of type double and can contain values only of that type).

Also, the Convert.ToDouble may throw exception if the user input is not valid. But I see you get the point of using Double.TryParse method, which returns true if the string (first parameter) is a valid number. So your addData method should look something like this:

//This method will add numbers to the array
public static void addData()
{
    double number;

    for (int i = 0; i < myArray.Length; i++)
    {
        Console.WriteLine("Enter a number you would like to add");
        // read user input
        string input = Console.ReadLine();
        // condition is true if user input is a number
        if (double.TryParse(input, out number))
            myArray[i] = number;
        else
            Console.WriteLine("Invalid input. Please enter a valid number");
    }
}

To find a number in your array you can use LINQ Contains extension method which does exacly that: it returns true if array contains element, otherwise false:

//This method will find a specific number within the array and check if it has already been entered
public static void findData()
{
    double number;
    Console.WriteLine("Find a number");
    string input = Console.ReadLine();
    // we use the same logic here as in the addData method to make sure the user input is a number
    if (!double.TryParse(input, out number))
    {
        bool found = myArray.Contains(number);
        if (found)
            Console.WriteLine("Array has number {0}", number);
        else
            Console.WriteLine("Array doesn't have number {0}", number);
    }
    else
    {
        Console.WriteLine("Invalid input. Please enter a valid number");
    }
}