2 Programming

Declaration is telling the computer what the identifier (name) should be and what type of data should be stored for a variable.

The allocation of data values to variables, constants, arrays and other data structures so that the values can be stored.

Value that can change during the running of a program. By convention we use lower case to identify variables (eg a=12)

Value that remains unchanged for the duration of the program. By convention we use upper case letters to identify constants. (e.g. PI=3.141)

a data structure refers to a way of organizing and storing data in a computer so that it can be accessed and used efficiently. e.g. arrays, 2-D arrays, data types.

2 ** 3, which equals 8

Input is collecting data, usually through the keyboard it is data sent to a computer to be processed

psuedocode: name <— USERINPUT python: name = str(input(“Enter your name: “)) psuedocode: variable = USERINPUT

Output is putting data onto the screen, usually as text it is processed info that is sent out from a computer

psuedocode: OUTPUT “text” python: print(“text”)

Character Real String Integer Boolean

Character data is a single letter of text data Eg. ‘a’

Real data is decimal numbers. Eg. ‘0.55’

String data is text data (multiple characters). Eg. “Hello”

Integer data is whole numbers. Eg. ‘12’

Boolean data is a true or false value. Eg. ‘True’ or ‘False’

The type of the data determines how it is stored and what you can do with the data.

Casting is the process of converting data from one type to another.

One of the most common reasons for casting is output. Output must be formatted as a string, and so we may need to convert a certain piece of data to a string. All input also comes as a string, and must then be converted to other data types.

Casting to a string can be done by using the str function Eg. str(3) gives “3”

Casting to an integer can be done using the int function. Eg. int(3.4) gives 3

Casting to a real can be done using the real function. Eg. real(“3.4”) gives 3.4

Operators are symbols that represent a specific function within a program

Integer division Modulus/modulo operator Basic Operators