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Add input validation to the below program by printing "You must enter a whole number." if the user enters a decimal or something that isn’t a number.

Wrap all of the code contained in the Main method in a try/catch block The catch block should catch FormatException exceptions Inside of the catch block, output to the console the message "You must enter a whole number."

How it get printed many times under the loop and why we use i+=1 ?

Program.cs
```using System;

namespace Treehouse.CodeChallenges
{
class Program
{
static void Main()
{
Console.Write("Enter the number of times to print \"Yay!\": ");
int count = int.Parse(input);
if(count > 0)
{

try
{

int i = 0;
while(i < count)
{
i += 1;
Console.WriteLine("Yay!");
}
}
}
else
{
Console.WriteLine("You must enter a positive number.");

}
catch(FormatException exception)
{
Console.WriteLine("You must enter a whole number.");

}

}
}
}
```

And the code "`i += 1`" is using the addition assignment operator to increase the value of "i" by 1. This way, "i" always has a count of the number of times the message has been printed. When it gets larger the the "count" that was asked for, the loop stops.