How to know what user entered in C#

Question

For Ex:

cw("enter anything");

//we dont know if user entered int or string or any other datatype so we would check as,

if(userEntered == int){}
if(userEntered==string){}

In other way: If user enters for example int value so we convert it and save it but if we dont know what user entered, how will we judge or detect?

*Everything* a user enters is a `string` - you have to (try to) convert it to see if it can be a specific type — UnholySheep, Oct 21 '16 at 19:33
the user will enter a string. You would try to parse it to whatever type you're hoping for. — Jonesopolis, Oct 21 '16 at 19:33
Usually program expects value of specific type. If it is integer, you should parse user's input and check, if entered value is integer. — Paviel Kraskoŭski, Oct 21 '16 at 19:35
What type is `userEntered`? Have you tried to parse string to int? — Markiian Benovskyi, Oct 21 '16 at 19:35
Use `int.TryParse()` https://msdn.microsoft.com/en-us/library/system.int32.tryparse(v=vs.110).aspx — 3Dave, Oct 21 '16 at 19:44

score 1 · Answer 1 · answered Oct 21 '16 at 19:34

1

For a console application taking in user input, assume its a string to begin with as string will be able to hold whatever the input is.

If needed, then you can parse it to another datatype such as ints or floats.

answered Oct 21 '16 at 19:34

danielku97

60
8

Coke · Answer 2 · 2016-10-21T19:51:49.863

public class MainClass
{
public static void Main(string[] args)
{
    String value = Console.ReadLine();
    var a = new MainClass();
    if a.IsNumeric(value){
    //your logic with numeric
    }
    else 
    {
    //your logic with string
    }
}

public Boolean IsNumeric(String value){
 try 
   var numericValue = Int64.Parse(value);
   return true;
 catch 
   return false;
}

In this case there is a separate function, which tries to convert it to number, if successful return true, otherwise false. With this you will avoid further code repetition to check if your value is numeric or not.

score 0 · Answer 3 · answered Oct 21 '16 at 19:34

There is no strict rule for that, User just enters a string value. It could be null or empty string or any other string, which might or might not be convertible to int or decimal or DateTime or any other datatype. So you just have to parse the input data and check whether its convertible to a datatype or not.

Timon Post · Answer 4 · 2016-10-21T19:42:28.270

0

 Console.WriteLine("enter someting");
 string read = Console.ReadLine();

Console.Readline() read user input and will return a string

From here try to convert/parse it to other data type.

edited Oct 21 '16 at 19:42

answered Oct 21 '16 at 19:35

Timon Post

2,779
1
17
32

score 0 · Answer 5 · answered Oct 21 '16 at 19:37

You can read user input through console.readline to check if it is a string or integer ,you can do something like this by default user input is string check the following code snippet

class MainClass
    {
        public static void Main(string[] args)
        {
            Console.WriteLine("Hello World!");
            string input = Console.ReadLine();
            Console.WriteLine(input);

            int num2;
            if (int.TryParse(input, out num2))
            {
                Console.WriteLine(num2);
            }
        }
}

score 0 · Answer 6 · answered Oct 21 '16 at 19:38

Here is an example to check if user enters integer or string value:

Console.WriteLine("Enter value:");
string stringValue = Console.ReadLine();

int intValue;
if(int.TryParse(stringValue, out intValue))
{
    // this is int! use intValue variable
}
else
{
    // this is string! use stringValue variable
}

score 0 · Accepted Answer · answered Oct 21 '16 at 19:39

Once you have your string input, you can use TryParse to see if it is an int or a decimal (among other things)...

string userEntered = Console.ReadLine();
int tempInt;
decimal tempDec;

if(int.TryParse(userEntered, out tempInt))
  MessageBox.Show("You entered an int: " + tempInt);
else if(decimal.TryParse(userEntered, out tempDec))
 MessageBox.Show("You entered a decimal: " + tempDec);
else MessageBox.Show("You entered a string: " + userEntered);

How to know what user entered in C#

7 Answers7