programming

Question 1

what is a variable

Answer 1

a memory location that is used to temporarily hold data value,
it can change while program is running

Question 2

benefits of subprograms:

Answer 2

easier to maintain: code is shorter, easier to understand
avoids repetition of code: sub can be called instead of copying/pasting, quicker to develop new programs
work can be delegated between team members, reduces development time

Question 3

count controlled loop to print out numbers 1 to 10 in ascending order

Answer 3

for i = 1 to 10
print i
next i

Question 4

what is high level language:

Answer 4

aimed to be understood by humans, has to be translated before it can be run

Question 5

Integrated Development Environment tools:

Answer 5

editor, to enable program code to be entered/ edited
translator, to enable code to be executed

Question 6

three programming constructs:

Answer 6

selection
iteration
sequence

Question 7

local variable advantages

Answer 7

saves memory - only uses memory when that local variable is needed - global variables use memory even if not used

easier to debug local variables as they can only be changed within one subroutine

you can reuse subroutines with local variables in other programs

Question 8

global variable advantages

Answer 8

variables can be used anywhere in the whole program (and in multiple subroutines)

makes maintenance easier as they are only declared once

can be used for constants - values that remain the same

Question 9

what is casting?

Answer 9

changing the data type of a variable to another data type

Question 10

why is casting needed?

Answer 10

-to concatenate two strings, the ALU needs to use numbers to perform the arithmetic operation
-therefore string needs to be ‘cast’ to a number

-integers require less bits of memory than real. numbers

Question 11

what is a boolean data type?

Answer 11

-true or false
-used to track if something has happened or happened or not

Question 12

return a string length:

Answer 12

length = string.length

Question 13

convert a string to all upper/lower case

Answer 13

ustring = string.upper
lstring = string.lower

Question 14

extract the ‘mat’ letter from
string = “tomato”

Answer 14

chars = string.substring(2,3)

Question 15

output PUT from someText = “Computer Science”

Answer 15

print ((someText.substring(3,3).upper)

Question 16

generate a random number betw 1 and 6:

Answer 16

myNum = random(1,6)

Question 17

advantages of using subprograms

Answer 17

• program is easier to write
• program is easier to debug
• creating reusable components
• functions could be gathered together into a library for easy reuse across multiple programs

Question 18

difference between functions and procedures

Answer 18

• functions return values and create reusable program components
• procedures create modular structure to a program making it easier to read

Question 19

create a function called ‘greeting’ to concatenate a name with hello

Answer 19

procedure greeting(“name”)
print(“hello” + name)
endprocedure

Question 20

describe how a character set is used to represent the string value stored in a variable

Answer 20

-each character has unique binary value
-binary value of each character store/combined (in order)

Question 21

Use pseudocode to write an algorithm that does the following :
*Inputs the title and year of a book from the user.
*Uses the librarycode function above to work out the book code.
*Permanently stores the new book code to the text file bookcodes.txt

Answer 21

title = input(“enter title”)
year = input (“enter year”)
code = librarycode(title, year)
myFile.writeLine(librarycode(title, year))
MyFile.close()