Computer Science Revision Guide
by Dan Chung
Flow charts are clear ways of displaying and planning out how you are going to create a code. The symbols on a flow chart represent different meanings/represent different things, i.e a variable is a diamond shape. Flow charts are a vital component to making code as they can be easily edited, they are also universally recognized, so everyone can understand it. It can be made using any language, meaning that you don't have to understand code in order to make on.
A subroutine is a set of instructions which perform a specific task for a main routine, a 'subroutine' can be accessed at any time. This helps decompose a large, complex program and convert it in to simple steps.