About an undesired type of user input

Question

Let's say I wanted the user to enter an integer but instead they entered a string value. How can I fix it?

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Console.WriteLine("Which day is it today in number?");
var day = Convert.ToInt32(Console.ReadLine());

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I tried to add a conditional to fix it like..

if (day != int)
Console.WriteLine("You can only enter a number!");

but it creates an error because it says I can't write "int" there..

So what can I do?

Answer 1

your if statement would be irrelevant, because an error would occur prior to even reaching that statement if the compiler tried to convert say “hi” to an integer. Typically I would suggest using a regex to compare whether or not the string entered contains only digits and handling the true/false return accordingly, but I do not know how to use regex matching in C#, so perhaps instead you could wrap the code in a try/catch block?

try {
Console.WriteLine("Which day is it today in number?");
var day = Convert.ToInt32(Console.ReadLine());
Console.WriteLine(day);
}
catch {
Console.WriteLine("You can only enter a number!");
}

Answer 2

Thanks a lot really! It works quite well thanks to your help :)
As a beginner now I need to learn more about try/catch blocks