Computational Constructs

Question 1

How is code modularity improved?

Answer 1

Keeping sub-programs as self contained as possible so they can be tested independently

Question 2

What is the scope of a variable?

Answer 2

the part / parts of the program where a variable can be used - eg local variables only exist within the sub program they are defined inside

Question 3

Why are global variables best avoided when possible?

Answer 3

They have global scope so can be accessed anywhere throughout the program. So their values can be altered unintentionally to bad effect

Question 4

What are sub-programs defined and called with?

Answer 4

Defined with formal parameters

Called with actual parameters

Question 5

What is a computational construct?

Answer 5

A combination of control structures which can be used to make solving programming programs more intuitive

Question 6

The scope of a variable describes…

Answer 6

Where it can be accessed from

Question 7

What is meant by variable declaration?

Answer 7

When a variable is created in a program

Question 8

What is a user defined function?

Answer 8

A sub-program written by the programmer which returns a value

Question 9

What is a method in an object-oriented language?

Answer 9

A function which is defined inside a class and can only be used in relation to an object of that class

Question 10

Parameters can be passed by….name and define both terms

Answer 10

Value: Parameters which are not changed when passed into a procedure (a local copy of the actual parameter is made and used inside the subroutine)
Reference: Parameters which may be changed by the procedure they are passed into

Question 11

What is unique about a sequential file compared to other input and output devices?

Answer 11

Treated in the same way but they have specific commands for opening and closing

Question 12

Function use

Answer 12

A category of sub program which will always return a single value to another part of the program

Question 13

Scope of a local variable

Answer 13

The sub program where it has been created

Question 14

Where are actual parameters listed?

Answer 14

On the call line used to activate a sub program

Question 15

Why is it unnecessary to use the same identifier (name) for related actual and formal parameters?

Answer 15

Most software development environments link parameters based on the order in which they are listed rather than their names
Allows for procedures/functions to be called several times with different values being passed in on each occasion

Question 16

How is an array usually passed and why?

Answer 16

By reference because passing an array by value would create too many copies which would place a large demand on RAM

Question 17

Pre-Defined Function

Answer 17

Already defined by the high level language, examples:random, round

Question 18

Call

Answer 18

Executes a sub-program from another part of a larger program

Question 19

What is necessary when listing formal parameters in the declaration/definition of a sub program?

Answer 19

The data type so that the sub-program can expect a type of data for the parameter to use

Question 20

Data Flow

Answer 20

The way in which data flows from one part of the program into another, e.g. from the main program into / back from a subroutine