2.3 Robust Programs Flashcards
What is Validation ?
Ensuring that any data input is possible and sensible.
What is a range check ?
the input must fall within a specified range.
What is a length check ?
the input must not be too long or too short.
What is a presence check ?
a data value must be entered
What is a format check ?
the data must be in the correct format
What is a type check ?
the data must be of a specified data type
What is a verification check ?
they repeat the entered data to the user and ask them to confirm if this data is correct.`
What is authentication ?
the process of a user confirming that they are who they say they are on a computer system
What are the 3 factors of authentication?
- something you are - username
- something you know - password
- something you have - swipe card, biometrics
What is the purpose of defensive design ?
that a program runs correctly and continues to run no matter what actions a user takes.
What are the 3 areas of defensive design?
- protection against unexpected user inputs
- maintainability
- minimising/removing bugs
How are anticipation and protection applied ?
- validation
- sanitisation
-authentication
-maintenance
- testing
What is the purpose of maintainability ?
to ensure that, over time, a program can be easily maintained.
How to increase maintainability ?
- Using comments
- Using naming conventions
- Using indentation
What are comments ?
Lines in programs that provide information about what the different parts of the program do.
What are naming conventions ?
Choosing a variable name that reflects the purpose of the variable.
What is Indentation ?
Code within selections or iterations should be indented
What are subprograms ?
small programs that are written within a larger, main program.
What are the two types of subprograms ?
- procedures
- functions
What are the benefits of subprograms ?
- small in size - easier to write, test and debug
- can be saved separately as modules - used again in other programs
- may be used repeatedly at various points in the main program.
What is a procedure ?
A procedure is a subprogram that performs a specific task
How is a procedure run ?
A procedure is run by calling it.
What is a function ?
works in the same way as a procedure, except that it manipulates data and returns a result back to the main program.
How is a function run ?
A function is run by calling it.
What are Libraries ?
contain pre-written, tested functions that extend the functionality of a language.
What are syntax errors ?
Not following syntax rules governing how to write statements
What are logic errors ?
Does not cause a program to crash but causes unexpected results.
What are the two types of testing ?
- Iterative
- Final (terminal)
What is iterative testing ?
Carried out while a program is being developed - repeats (iterates) until the module works as intended.
What is final (terminal) testing ?
All modules are complete and the program is tested as a whole
What is valid testing data ?
- sensible, possible data that the program should accept and be able to process.
What is extreme testing data ?
- valid data that falls at the boundary of any possible ranges
What is invalid (erroneous) testing data ?
- data that the program cannot process and should not accept.
What is a test plan ?
A list of what is to be tested and how it is to be tested.
What are bugs ?
An error in a program.
