I need a console app that changes the sign to a certain typed number. You type 10, it gives you -10. And so on. I've managed to do that, but I can't do it if I type 1.5 for example. Or any decimal number. I get "Input string was not in a correct format". this is what I did.

string inputData = Console.ReadLine();
int a = Convert.ToInt32 (inputData);
int b = a * (-1);
Console.WriteLine(b);
Console.ReadLine();

CodePudding user response：

1. You need to use decimal as a variable type if you want to work with decimal numbers
2. If so, use Convert.ToDecimal instead of ToInt32
3. You don't really need to use multiplication here, it's enough just to use -a instead

string inputData = Console.ReadLine();
decimal a = Convert.ToDecimal (inputData);
decimal b = -a;
Console.WriteLine(b);
Console.ReadLine();

CodePudding user response：

Alexay's comment is correct. But you also will need to change your variable types to float, double or decimal depending on the constraints of the program.