2.2.1 Programming techniques

Question 1

2.2.1 A)
What’s a programming construct used for.

Answer 1

used to represent control flow structured programming

Question 2

2.2.1 A)
What are the 3 programming constructs.

Answer 2

Sequence , branching/selection , iteration

Question 3

2.2.1 A)
What is a sequence in term of programming constructs.

Answer 3

Code is executed line by line top to bottom

Question 4

2.2.1 A)
What is branching / selection in term of programming constructs.

Answer 4

Code is run if a specific condition is met (if statement)

Question 5

2.2.1 A)
What is iteration in term of programming constructs.

Answer 5

Code is executed certain number of times or while a condition is met. (for/while statement)

Question 6

2.2.1 B) What is recursion

Answer 6

A construct in which a subroutine calls apron itself during execution. This continues until a certain condition is met ( stopping condition ).

Question 7

2.2.1 B)
What is recursion like and how is it different.

Answer 7

produces the same result as iteration but suited to certain problems.

Question 8

2.2.1 B)
What’s the advantage of recursion.

Answer 8

CAN be represented in fewer lines which can lead to less errors. But it needs to be clearly defined to reach a stopping condition

Question 9

2.2.1 B)
How do stacks work in recursion.

Answer 9

Every time the stack calls itself a new stack frame is created within the stack. Stack frames are created until stopping condition is met and subroutine unwinds. Information from the call stack being popped off the stack.

Question 10

2.2.1 B)
What is recursion used for?

Answer 10

For storing parameters, local variables and return addresses are stored allowing the subroutine to return to a particular point during execution.

Question 11

2.2.1 B)
What’s the disadvantage of recursion

Answer 11

inefficient use of memory, danger of stack overflow (if it calls it self too many times call stack runs out of memory) this can lead to the program crashing, Difficult to trace.

Question 12

2.2.1 B)
How can recursion be improved ?

Answer 12

can use tail recursion its a form of recursion which implemented in a more eff way, less stack space is needed

Question 13

2.2.1 C)
What is scope

Answer 13

refers to the section of code the variable is available too.

Question 14

2.2.1 C)
What is a local variable

Answer 14

It has a limited scope, only can be accessed within a block of code in which they were defined.

Question 15

2.2.1 C)
Adv of local variable

Answer 15

multiple local variables can have same name not effect each other. good practice ensures subroutines are self contained.

Question 16

2.2.1 C)
What is a global variable

Answer 16

can be accessed across whole program its declared outside of a subroutine

Question 17

2.2.1 C)
dis(adv) of global variable

Answer 17

useful for values used by multiple parts of program
can be unintentionally overwritten / edited

Question 18

2.2.1 C)
When are global / local variables deleted.

Answer 18

Global variables deleted after the program finishes executing ( takes up more memory)
Local variables deleted after subroutine finishes

Question 19

2.2.1 C)
What happens if a local and global variable have the same name

Answer 19

local takes precedence

Question 20

2.2.1 D)
What is modular programming

Answer 20

A technique used to split large, complex programs into smaller, self contained modules.

Question 21

2.2.1 D)
What is top down approach / stepwise refinement

Answer 21

problems continually broken down into sub problems until it can be represented as individual, self contained black box which preforms a certain task.

Question 21

2.2.1 D)
What is the adv of modular programming

Answer 21

makes problem easier to understand and approach. Also makes it easier to divide takes between a team and manage. This improves testing / maintenance as its dealt with individually therefore improving reusability .

Question 22

2.2.1 D)
What are procedures and functions

Answer 22

modules form subroutines which can be categorized as either functions or procedures

functions named blocks of code that performs a specific task. function must always return one value and typically use local variables

procedures named block of code that performs a specific task. procedures dont have to return a value but can also return multiple values

Question 23

2.2.1 D)
How can parameters passed through to a subroutine

Answer 23

Either by value or by reference

Question 24

2.2.1 D)
What happens when parameter is passed by value

Answer 24

They are treated like a local variable. a copy is made passed through subroutine it is discarded at the end, value outside of subroutine unaffected.

Question 25

2.2.1 D)
What happens when parameter is passed by reference

Answer 25

Address passed through, address given to the subroutine so the value of parameter will be updated at given address

Question 26

2.2.1 D)
Which parameter passing should be assumed

Answer 26

By value unless told otherwise

Question 27

2.2.1 E)
What is an IDE and what is it used for

Answer 27

Integrated design environment
a program which provides a set of tools to make writing , developing and debugging code easier,

Question 28

2.2.1 E)
Common feature of IDE

Answer 28

Stepping
Variable watch
Breakpoint
Source code editor
Debugger tool

Question 29

2.2.1 E)
Common feature of IDE
What is stepping

Answer 29

monitor effect of each line of code by executing a single line at a time

Question 30

2.2.1 E)
Common feature of IDE
What is variable watch

Answer 30

Sometimes used to pinpoint errors observe how content of variable change in real time

Question 31

2.2.1 E)
Common feature of IDE
What is breakpoint

Answer 31

set a point in the program at which program will stop based on condition or specific line helps pinpoint error.

Question 32

2.2.1 E)
Common feature of IDE
What is source code editor

Answer 32

make writing easier with auto completion of words, indentation, syntax highlight

Question 33

2.2.1 E)
Common feature of IDE
What is debugging tool

Answer 33

run time detection of errors with a guild to where in the code likely to be. Through line number / highlights.