Graham will use an event driven programming language to create the program code.(b) Describe the purpose of a ‘trigger function.

A 'trigger function' in an event-driven programming language is a specific type of function that is designed to execute or 'trigger' when a certain event occurs.

The purpose of a trigger function is to handle specific events such as user interactions (like clicks, key presses, or mouse movements), system events (like system startup or shutdown), or program-defined events (like variable changes or errors).

For example, if Graham is creating a program where something happens when a user clicks a button (like opening a new window, or starting a game), he would write a trigger function that is linked to the 'button click' event. When the button is clicked, the event-driven programming language automatically calls the trigger function, and the code within that function is executed.

So, in summary, the purpose of a trigger function is to respond to specific events by executing code. This allows for interactive and responsive programming, where the program can react to user input or system changes.