Exceptions Errors

try

{

    // put the code here that may raise exceptions

}

catch

{

    // handle exception here

}

finally

{

    // final cleanup code

}

Custom Exception

public class CustomException: Exception

{

    public CustomException() { }

    public CustomException(string message) : base(message) { }

    public CustomException(string message, Exception innerexception) : base(message, innerexception) { }

} 

Sample

throw new ArgumentOutOfRangeException(nameof(amount), "Amount of deposit must be positive");

throw new InvalidOperationException("Not sufficient funds for this withdrawal");