我是初学者，编写控制台程序 我正在尝试构建计算器并需要帮助 (C#)

Question

I want to know how to use a user input similar to Convert.ToInt64(Console.Readline()) but if they type eg: 198.98

Into the floating point type you prefer var doesn't work I don't know what else to do

Answer 1

you can use this:

float.TryParse(Console.Readline());

Answer 2

You should use this method instead of using the Convert class. If you want to make sure your program doesn't throw an exception, try float.TryParse() instead.

var f = float.Parse(Console.ReadLine());

Console.WriteLine(f);
Console.ReadLine();

Answer 3

What does the var part look like?

Answer 4

You should check the input parameter and then try to cast it. use try parse to cast

    if(double.TryParse(request.Code, out var doubleNumber))
    {
        throw new ArgumentException();
    }

read this doc: https://docs.microsoft.com/en-us/dotnet/api/system.double.tryparse?view=net-6.0

Answer 5

Make sure that the user only can input number.

var a = float.Parse(Console.ReadLine());

Console.WriteLine(a);

Or

double b = Convert.ToDouble(Console.ReadLine());

Console.WriteLine(b);

You can also read this article

https://docs.microsoft.com/en-us/dotnet/csharp/tour-of-csharp/tutorials/numbers-in-csharp-local

Answer 6

We have various options for performing this conversion. The difference between float and double is that float has four places after the decimal point and double has twelve places after the decimal point. So of you want double you can use it as,

var num = Convert.ToDouble(Console.ReadLine())

In case if you want to convert it into float we have two options there, parse and tryparse. Parse returns the converted number and TryParse returns the Boolean value of conversion. You can use it accordingly like,

var num = float.Parse(Console.ReadLine())

Answer 7

try this one: for your situation you have to use below code:

Convert.ToDouble(Console.Readline());