Check if input has number and string to calculate in C#

Question

I am really into the basics of programming and while writing a few lines of code to convert Celsius to Fahrenheit, which is pretty easy I started to wonder the following: Can I make the program show me an answer depending if I wrote in the Console: 25C //to convert to F or for example 100F // to convert to C

So far my knowledge goes to advanced "if" constructs and "for" cycles. Just started to study "do-while".

I am missing some knowledge how to properly search an input for number && specific char in order to give proper calculation.

I know that it seems a little complicated to make input : 25F // in one line instead of

25

F

but this will expand my knowledge and understanding. I will try the latter now, should be easy, but can't find out how to do the former.

Thanks in advance! Darin

Eiver · Accepted Answer · 2018-09-02 17:21:30Z

4

In C# any string is actually a class, which contains useful methods for example:

        string input = "25F";

        if (input.EndsWith("F"))
        {
            // handle Fahrenheit
        }

Then you can get rid of the last character like so:

string inputWithoutLastCharacter = input.Substring(0, input.Length - 1);

To convert a string to a number you can:

    try
    {
        int number = int.Parse(inputWithoutLastCharacter);
    }
    catch (Exception ex)
    {
        Console.WriteLine("Could not convert your input to a number " + ex.ToString());
    }

Try/catch is there to handle error cases where the input is not a valid number. Also check out other methods of string. For example ToLower() to handle both "f" and "F".

Good luck.

answered Sep 2, 2018 at 17:21

Eiver

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3 Comments

Parrish Husband Over a year ago

Why not int.TryParse?

dotNetD Over a year ago

Eiver, thank you for your unexpectedly prompt reply! That is really useful and more than enough.I have to learn more about string methods and manipulation. I dived into the dev world just two months ago, but focused on "programming basics" mere two weeks ago as I wanted to prep for this course. A friend from school, has a lifetime passion to make talented devs, created SoftUni in Bulgaria and has more than 25 yrs of experience as software engineer. His name is Svetlin Nakov. So I trust his tuition program and will hold on to my brain to succeed!

Eiver Over a year ago

int.TryParse() is just as good. In the old days when exceptions were slow, it would be actually even better. But why not introduce exceptions for educational purposes? :D Also with exceptions you know what went wrong from the exception type and message. It really depends what you need.

Mert Sarıözkan · Accepted Answer · 2018-09-02 17:59:51Z

0

    String temp = Console.ReadLine();
    char scale = temp[temp.Length-1];
    if(temp.ToUpper().Contains("F")) {
        int temperature = Int32.Parse(temp.Remove(temp.Length-1,1));
        double celciusValueOfTemp = (temperature-32)/1.8;
        Console.WriteLine(celciusValueOfTemp);
    }
    else if(temp.ToUpper().Contains("C")) {
        int temperature = Int32.Parse(temp.Remove(temp.Length-1,1));
        double fahrenheitValueOfTemp = temperature*1.8+32;
        Console.WriteLine(fahrenheitValueOfTemp);
    }

answered Sep 2, 2018 at 17:59

Mert Sarıözkan

16

1 Comment

dotNetD Over a year ago

Mert, thats extremely useful. Highly appreciate that. Seems I need to learn most string methods to have a larger toolbox.

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