2.2.1 FINAL Programming techniques

A classification of data into groups

Used to represent whole numbers, either positive or negative

Used to represent numbers with a fractional part, either positive or negative

Used to represent a single character such as a letter, digit or symbol

Used to represent a sequence of characters

Used to represent true or false values

When you convert one data type to another data type

Determines the order in which lines of code are executed

Sequence, Branching, Iteration

• Refers to lines of code which are run one line at a time • The lines of code are run in the order that they are written from the first line of code to the last line of code

• The flow of the program is interrupted and a condition is tested • Outcome of the condition will then determine which lines/block of code is run next. Two ways to write selection statements: • IF statement: test conditions sequentially SWITCH statement: test an expression against multiple possible constant values

• Repeating a line or block of code using a loop. It can be: • Count controlled: When the code is repeated a fixed number of times (for loop) • Condition controlled: When the code is repeated until a condition is met (while loop)

• Type of conditional statement that provides an alternative way to perform multiple comparisons based on the value of an expression • Useful when you have a single expression that you want to compare against multiple possible values

Count controlled loop that will repeat a fixed number of times

Condition controlled loop that will repeat until a condition is met - Provides a flexible way to handle situations where the number of iterations in unknown in advance

Where problems are broken down into more manageable pieces - Each piece of the problem should be carried out by one single subroutine

• Standalone blocks of code and when called, they will complete a task • The promote code reusability, modularity and organisation, enabling a programmer to write efficient and maintainable programs

Block of code that takes in 0, 1 or more parameters, performs a set task and return a value

Block of code that takes in 0, 1 or more parameters and performs a set task

Pieces of data which are passed into the function or procedure to allow it to complete a task

• Passing by value • Passing by reference

• A copy of the actual value is made and assigned to the function’s parameter • Any changes to the parameter within the function’s scope do not affect the original value outside the function • Function works w/ and changes its own local copy of the value • Suitable when you want original data to be protected from being modified within the function • When function ends, copy of the value is destroyed • Can lead to performance overhead when working with large data structures since a copy is made

• Function receives the memory address of the value rather than a copy of the value • Any changes made to the parameter within the function directly affect the original value outside the function • Both the function and the calling code share the same memory location • Efficient for working w/ large data structures • Can lead to unexpected side effects if not handled carefully, as changes made within the function affect other parts of the program

When a function calls itself to solve a problem or execute a task - Uses idea of self-reference to break down complicated problems into more manageable subproblems