Programming

why should you use the correct data type? (3)

• makes code more memory efficient

• code is more robust

• code is more predictable

define casting

changing the data type of a variable to another data type

what does the ASC() function do?

converts a character into its ASCII number

what does the CHR() function do?

converts an ASCII number into its equivalent character

exponentation operator

^ pseudocode ** python

what does MOD do

returns remainder

what does DIV do

removes remainder to return whole number

define variable

named location in memory which can change during the running of the program

what is a constant

an assigned data value that can’t be changed

what would x.left(2) do on the string x=”Hello”

extract the first 2 characters = “He“

what would x.right(3) do on the string x=”Hello”

extract the last 3 characters = “llo”

what would x.subString(2,2) do on the string x=”Hello”

extract the characters starting at position 2 with a length of 2 = “ll”

NOT gate truth table

AND gate truth table

OR gate truth table

differences between arrays and lists (2)

• arrays store data of the same data type, lists can store data of different data types

• arrays have a fixed length but lists can change length

array rowers[4]

creates an array called rowers which can hold 4 elements

code to open a file called file.txt stored in a variable myfile for writing

myfile = open(“file.txt”,”w”)

code to open a file called file.txt stored in variable myfile

myfile = open(“file.txt”)

code to close a myfile

myfile.close()

code to read next line of myfile

myfile.readLine()

code to add “hello” to the end of myfile

myfile.writeLine(“hello”)

code to check if at the end of the file

myfile.endOfFile()

code to create a new file called mytext.txt

newFile(“mytext.txt”)

code to print on a new line

\n

are records fixed length or static?

fixed length

problems with flat file databases (3)

• data redundancy

• inaccurate data

• inconsistent data

define procedure

sets of instructions stored under one name which are executed when called.

difference between a function and a procedure

functions return a value, procedures do not return a value

procedures don’t always need a parameter, functions always need at least one parameter

functions must be inside print statements or assigned to variables or the value returned is lost.

#procedure
subject()

#function
subject = favourite(computer)

when are subprograms useful? (3)

• repeating code

• better structure and readability of code

• reduces the amount of code you have to write

what is the difference between an argument and a parameter?

• parameters are used to pass values into a subprogram

• arguments are the actual values that parameters take when subprograms are called

# Function definition with parameters
def add(x, y): # x and y are parameters
   return x + y

# Function call with arguments
result = add(5, 3) # 5 and 3 are arguments
print(result) # Output: 8

define local variable

variables that can only be used in the structure they are declared in

define global variable

variables that can be used anywhere after their declaration