Regular expression for validating a number
Since you no longer would have to worry about the highest group number and area number that had been assigned.However, you still can't just go throwing any values into there and expecting it to be valid as the Social Security Administration still has a few Social Security Numbers that are explicitly "off limits" as mentioned below.Before we look at the code sample, I would like to provide a little explanation of Regular Expressions.Regular Expressions are specially formatted strings for specifying patterns in text.So is there anyway to write a regular expression to check whether a number is in (-2055, 2055) or not ? It is easier to use if statement to check whether the number is in range or not. If one or more fields are empty then the program displays a message to the user that all fields must be filled in before the program can validate the input information.The code above calls the first Name Text Box's Focus method to place the cursor in the first Name Text Box.
In addition, since regular expressions analyze strings, numbers must first be translated to a string before they can be tested. If there is a match, then the event handler proceeds to validate the first name.This process continues until the event handler validates the user input in all the Text Boxes or until a validation fails.:5[0-5] //50 through 55 | //or [0-4][0-9]) //00 through 49 | //or 1[0-9] //a one followed by any three digits | //or [1-9][0-9] //1-9 followed by 0 through 2 of any digit | //or (? It's an interesting exercise, because you can think of two distinct method: roughly, you can either: Without trying, how would you know which is best? (With thanks to Plasma Power and Casimir et Hippolyte for the debugging assistance.) Depending on what you are capturing, it is likely that all sub-groups should be made into non-capture groups. It turns out that the first approach (aliteralmind's answer) is far more economical. Speed Tests Here is the output of my simple speed test, matching from -1M to 1M.
Compilers use Regular Expressions to validate the syntax of programs.