I am writing a Mathematica command that prompts the user to enter a number.

The "script" stores the user input and then performs a calculation. I want to make sure that the user input is a number, and not a string.

I am looking for a concise check for this constraint.

This is what I came up with:

age = InputString["What is your age?"];
If[NumberQ[ToExpression[age]],
 Print["You are ", age, " years old."],
 Print["Please enter a number for your age."]

For example, what if the user enters 'seven teen' (so that age = "seven teen")? Same question may arise if I want the input to be a positive number, and not a negative number (user input is '-9').

Is there a faster way to make this check, other than an If conditional?

I came over this tutorial - Putting Constraints on Patterns, and saw these two lines:

pattern/;condition

and

pattern?test

I am asking you for help on how to implement them in the above context.

I am familiar with the built-in testing functions such as NumberQ, NumericQ and Positive[x]. I just don't have deep understanding of what the pattern is.

The condition, or test, is whether NumberQ[age] returns True, as I understand it now.