How to make sure that a 4 number input is 4 getting numbers?

Question

My input is a year in 4 digits between 1900-3000. So the input has to be 4 digits 1994, 2022,2950.

However, how do I check if the input is only 3 digits or less or 5 digigts or more? I have alread made an if statement if it's over 1900 or 3000.

   if (YearNumb<1900 || YearNumb>3000)
        {
            Console.WriteLine("Du angav inte ett år mellan 1900 och 3000.");
            Console.ReadLine();
            return;

`if(yearNumb < 1000 || yearNumb > 9999)` – Habib Feb 10 '14 at 17:08 — Habib, Feb 10 '14 at 17:08
It is an int converted from a string – Essej Feb 10 '14 at 17:45 — Essej, Feb 10 '14 at 17:45

user1948635 · Accepted Answer · 2014-02-10T17:17:50.620

4

if (YearNumb<1900 || YearNumb>3000)
        {
            Console.WriteLine("Du angav inte ett år mellan 1900 och 3000.");
            Console.ReadLine();
            return;
        }
else if (YearNumb.ToString().Length != 4)
           {
            Console.WriteLine("text");
            Console.ReadLine();
            return;
        }

Convert to string and check length.

edited Feb 10 '14 at 17:17

answered Feb 10 '14 at 17:07

user1948635

1,357
4
15
22

Doesn't work properly, if I enter 1700 it does not execute it. – Essej Feb 10 '14 at 17:15
Oops, edited above to solve that issue and the ability to show a different message. – user1948635 Feb 10 '14 at 17:17
@Baxtex, there is no way that the second `if` will ever be entered. Its a pointless `ToString()` call followed by a redundant length check. If `YearNumb` is an `int` it cannot be between `1900` and `3000` and have a length other than `4`. Unless, I suppose, the culture you are under has a non decimal representation for numbers. – Jodrell Feb 11 '14 at 09:21

Jodrell · Answer 2 · 2014-02-11T09:37:06.047

-1

ok,

if (YearNumb < 0)
{
    ...
} 
else if (YearNumb < 1000)
{
    ...
}
else if (YearNumb > 9999)
{
    ...
}
else if (YearNumb < 1900 || YearNumb > 3000)
{
    ...
}

Is probably more like what you are looking for.

edited Feb 11 '14 at 09:37

answered Feb 10 '14 at 17:10

Jodrell

34,946
5
87
124

A number with 3 or 5 characters will pass int.tryparse – user1948635 Feb 10 '14 at 17:19
@user1948635 but, the parsed value won't be geater than `1899` and less than `3001`. So `valid` will remain `false` unless `input` is valid. – Jodrell Feb 10 '14 at 17:26

How to make sure that a 4 number input is 4 getting numbers?

2 Answers2