C#•3y ago

Solved

I have made a square root calculator It works when someone enters an invalid Input to the square root it repeats however, when it says to enter the decimal value and there is a error it goes through the try-catch and goes and repeats the method. I would like for when the user is asked to input a number of decimals and when invalid input is typed it will repeat that question https://github.com/AbdulRaheemNazir/MiniApps/blob/main/Square%20Root%20help here is the link to the code, any help would be appreicated it

GitHub

MiniApps/Square Root help at main · AbdulRaheemNazir/MiniApps

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12 Replies

ero•3y ago

$tryparse

MODiX•3y ago

The TryParse pattern is considered best practice of parsing data from a string: - a TryParse method returns true or false to inform you if it succeeded or not, so you can use it directly in a condition, - since C# 7 you can declare a variable that will be used as an out argument inline in an argument list, - it forces you to check if the out argument contains valid data afterwards, Avoid: Convert.ToInt32 — it's a bad choice for parsing an int. It exists only for backwards compatibility reasons and should be considered last resort.

return Convert.ToInt32(null); //returns 0. null should not be considered as 0 ever
return Convert.ToInt32("asdf"); //throws FormatException

return Convert.ToInt32(null); //returns 0. null should not be considered as 0 ever
return Convert.ToInt32("asdf"); //throws FormatException

(Note: Convert does contain useful conversion methods: To/FromBase64String, To/FromHexString, ToString(X value, int toBase), ToX(string? value, int fromBase)) Avoid: int.Parse — you have to use a try/catch statement to handle invalid input, which is a less clean solution.

var number = int.Parse("abc"); //throws FormatException
var number = int.Parse(""); //throws FormatException

var number = int.Parse("abc"); //throws FormatException
var number = int.Parse(""); //throws FormatException

Use int.TryParse https://docs.microsoft.com/en-us/dotnet/api/system.int32.tryparse?view=net-5.0#System_Int32_TryParse_System_String_System_Int32__

if (int.TryParse(someInput, out var result))
{
  Console.WriteLine($"Thanks for giving me the following number: {result}!");
}
else
{
  Console.WriteLine("You didn't give me a valid number :c");
}

if (int.TryParse(someInput, out var result))
{
  Console.WriteLine($"Thanks for giving me the following number: {result}!");
}
else
{
  Console.WriteLine("You didn't give me a valid number :c");
}

Int32.TryParse Method (System)

Converts the string representation of a number to its 32-bit signed integer equivalent. A return value indicates whether the operation succeeded.

Unknown User•3y ago

Message Not Public

maroonlolOP•3y ago

So the restart of the question is fine for int number But for the int numberofdecimalplaces how woul I get it to repeat that question again

Unknown User•3y ago

Message Not Public

maroonlolOP•3y ago

Thank you for your help -------------------------------------------- forget everything i said above issue is now fixed -------------------------------------------------

maroonlolOP•3y ago

https://github.com/AbdulRaheemNazir/MiniApps/blob/main/Repeat%20asking%20for%20decimal%20number

GitHub

MiniApps/Repeat asking for decimal number at main · AbdulRaheemNazi...

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maroonlolOP•3y ago

Everything works but I want it to repeat asking the user for a valid decimal number i have added a while loop but i dont think i have implemented it right as when i write a invalid decimal number it leads me to the start of the program Anyone?

Kouhai•3y ago

numberofdecimalplaces > 0 & numberofdecimalplaces < 7 You're using bitwise and & You should use && i.e logical and

maroonlolOP•3y ago

Good spot, thank you but that I don't think would make a difference to the problem I'm facing

Kouhai•3y ago

Right, it won't really affect the execution, I don't see any bug tbh, the program will keep asking for numberofdecimalplaces until it's provided a valid one

maroonlolOP•3y ago

Oh it does work🤣I was looking at the old version😭😭

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