2.2.1 Programming techniques

-sequence -selection -iteration

-executing instructions one after another

-allows a program to change direction depending on the outcome of a condition (boolean expression) -e.g an IF statement

-repeating sections of code -could be a FOR loop (a count-controlled loop) -could be a WHILE, DO…UNTIL or a REPEAT…UNTIL loop (condition controlled loop)

-when a subroutine (often a function) calls itself from within its own subroutine

-contains a stopping condition (base case) -the subroutine should call itself for any input value (other than the base case) -stopping condition should be reachable within a finite number of times

-it may call itself indefinitely, resulting in stack overflow

-declared inside a subroutine -only accessible by that subroutine -created when the subroutine is called -destroyed when the subroutine ends

-declared at the top of a program, outside of any subroutine -accessible throughout the program -created when the program starts -destroyed when the program ends

-can make programs hard to test, debug and maintain -using global variables is generally considered poor programming practice

-procedure -function -subroutine -method

-a block of code that takes in zero, one or more parameters and performs a set task

-a block of code that takes in zero, one or more parameters; performs a set task; and returns a value

-The concept of breaking a large program/ problem down into smaller chunks -each module carries out a single specific task

-by value -by reference

A program that provides a set of tools and related functionality designed to maximise a programmers productivity

-code editors -error diagnostics (reports errors) -runtime environments -translators -auto documentation -syntax highlighting -autocompletion