Topics / Programming / Validation


Validation is an automatic check to ensure that data entered is sensible and feasible.  Validation cannot ensure data is accurate.

When programming, it is important that you include validation for data inputs. This stops unexpected or abnormal data from crashing your program and prevents you from receiving impossible garbage outputs.

Validation methods

Validation Method Description
Range check Checks the data falls between an acceptable upper and lower value, within a set range
Type check Checks that the data entered is of an expected type, e.g. text or a number
Length check Checks the number of characters meets expectations, e.g. an 8 character password
Presence check Checks that the user has at least inputted something, stopping them from accidentally entering nothing
Check digit An extra digit added to a number which is calculated from the other digits, this ensures the rest of the number has been entered properly


Topics / Programming / Validation