DESIGN, TESTING, IDEs

Question 1

what do structure diagram show

Answer 1

smaller tasks of a larger program

Question 2

what are the advantages of using structure diagrams

Answer 2

• coding can be easier as you’re writing code to carry out simple tasks
• many programmers can work on 1 program as each module can be written independently
• easier to test as each module can be tested
• individual sub programs and modules can be fixed and updated without affecting the rest of the program
• able to reuse sub programs and modules in programs you write in the future

Question 3

why should your program be well-maintained

Answer 3

makes it easy for other programmers to understand what the code does

Question 4

how can you make your program well-maintained

Answer 4

• comments using #, useful to explain whats happening
• indentation, to separate different statements in a program
• naming variables appropriately, helps to understand what they do and can keep track of it easily
• using sub programs, help other programmers to see different parts of a program work

Question 5

what is defensive design used for

Answer 5

to ensure program functions correctly and never produce errors

Question 5

what is input validation

Answer 5

checking if data meets certain criteria before passing it into the program

Question 6

how can you protect your program using defensive design

Answer 6

• anticipate how users might misuse the program and preventing it
• ensure code is well-maintained
• reduce number of errors by testing

Question 7

name 2 examples of input validation

Answer 7

length check, range check

Question 8

how does authentication protect your program

Answer 8

confirms identity of user before they are allowed to access certain pieces of data

Question 9

how can you increase the security of a password-based authentication system

Answer 9

• force users to create strong passwords and change them regularly
• limit number of failed password attempts

Question 10

what is a syntax error

Answer 10

when the compiler or interpreter doesn’t understand something because it doesn’t follow the rules/grammar of the programming language

Question 11

what is a logic error

Answer 11

when the compiler or interpreter is able to run the program but the program does something unexpected

Question 12

what are the 2 main types of testing

Answer 12

• iterative testing (testing while being developed)
• final testing (testing after program is finished being developed

Question 13

When testing data what is normal, boundary, invalid and erroneous data

Answer 13

normal = things that a user is likely to input in a program
boundary = values at the limit of what the program can handle
invalid = inputs with the correct data type that should be rejected by the program
erroneous = inputs with an incorrect data type that should be rejected by the program erroneous

Question 14

what is low-level language and name 2 examples

Answer 14

source code that is tricky for humans to read and write but easy for a computer to run
machine code and assembly language

Question 15

what is high-level language and name 2 examples

Answer 15

source code that is easy for humans to write but computers need to translate it before hey can read and run it
python and C++

Question 16

what does a compiler do

Answer 16

translate high-level code directly into machine code

translates all of the source code at the same time to create 1 executable file

Question 17

what does a interpreter do

Answer 17

translates and runs the source code 1 instruction at a time, but doesn’t create an executable file

Question 18

what are the differences between compilers and interpreters

Answer 18

• compilers are only need once, interpreters are need each time you want to run the program
• compilers returns a list of errors for the entire program, interpreter will return the first error it finds and the stop
• compilers can run the program very quickly after being compiled, interpreter runs more slowly as code is being translated while running

Question 19

what does IDE stand for

Answer 19

integrated development environment

Question 20

what is the main purpose of an IDE

Answer 20

software that provides features to help a programmer to develop their program

Question 21

what are 5 common features of an IDE

Answer 21

• code editor (main part), where the code is written
• output window, shows the output from a program when it is run
• line numbering and automatic code colouring
• error diagnostics to help find and fix errors in a a program
• a translator (compiler or interpreter) allows source code to be understood by the computer