Question How do I ensure entered data is numerical?

[Adam]

Hello,

How could I ensure that the data entered in the following code is numerical?

        Console.Write(CurrentPlayer & " enter x coordinate: ")
        XCoordinate = Console.ReadLine()
        Console.Write(CurrentPlayer & " enter y coordinate: ")
        YCoordinate = Console.ReadLine()
        Console.WriteLine()

Sorry if it's a bit of a noobish question, it's a rather new language to me, lol.

Many Thanks,

Adam.

 

[JohnH]

Dim number As Integer
If Integer.TryParse(xCoord, number) Then 
    'String input is a Integer and the numeric value is now in 'number' variable.
End If

 

[HosseinRad]

You can use IsNumeric Function

This function return a boolean value.if the string is number then return true or else false

Put your string into ( )

For Ex:
If IsNumeric("Rad") = True Then....

 

[JohnH]

You can use IsNumeric Function

This function return a boolean value.if the string is number then return true or else false

Put your string into ( )

For Ex:
If IsNumeric("Rad") = True Then....

Next you need to convert the String value to a numeric value... why not just use the single TryParse call that both validate and converts when possible?

 

[HosseinRad]

Dear JoHN

I told he can so use this method.
and for use IsNumeric Function is not Necessary to convert your string to number by val()

 

[JohnH]

It is obvious Adam needs to convert the string input to numeric data, so your IsNumeric suggestion falls short.
Also, Val function returns a Double, so if you need Integer you must convert it again.

 

[HosseinRad]

Sorry, but Val function return a Decimal value!
And do not need to convert again!

 

[JohnH]

Nope, if you use it with a String value argument you get a Double: Val Function
And as I said, if you require an Integer value you must convert the Double value to Integer value, adding yet one more operation. All primitive types has a TryParse representation, so this is win-win situation if you want to do what is asked about in this thread.