Bubble Sort

Reusable Code Blocks

Imagine writing instructions for making tea. Instead of writing "boil water" every time, you could say "see 'boiling water' instructions on page 5". Subprograms (functions and procedures) work the same way - write code once, use it many times by "calling" it. Functions return a value (like a vending machine giving you a drink). Procedures just do something (like pressing a button that turns on a light).