Validating input in perl dating aamna

08 Sep

More information on Github Developers are welcome to get involved by contributing code, either to existing tools or proposed future projects.Testing, bug reports, suggestions, or help in creating good documentation are also important!Now let’s take a look at another example where we are going to ask the user to enter their phone number.Unlike a user’s name, which is variable-length and where the validation criteria are the same for every character, a phone number is a fixed length but the validation criteria differ depending on the position of the character.However, C does not have built-in regular expression support (it’s supposedly coming with the next revision of C ), so typically this is done by examining each character of the string to make sure it meets some criteria.With numerical validation, we are typically concerned with making sure the number the user enters is within a particular range (eg. However, unlike with string validation, it’s possible for the user to enter things that aren’t numbers at all -- and we need to handle these cases too.are valid characters in the user input, this function won’t work, because those symbols have been given special meanings.

If the user enters input starting with a letter, cin.fail() will be true, and we will go into the conditional.Consequently, we are going to take a different approach to validating our phone number input.In this case, we’re going to write a function that will check the user’s input against a predetermined template to see whether it matches. Otherwise, the characters in the user input and the template must match exactly.Thus, such a template could not be used to ensure the user enters two words separated by a whitespace, because it can not handle the fact that the words are of variable lengths.For such problems, the non-template approach is generally more appropriate.