What is a Computer Program?

A computer program is a receipe for solving a problem. A fancy word for a receipe is an `algorithm'.

A receipe says:
`Do this, do this, if this happens do that ... etc.'

This is also what a computer program says. It is just a list of instructions, some of which will be qualified by statements equivalent to: `Do this three times' or `Do this until the sauce thickens' or `Do this if it starts to go lumpy'.

The computer receipe must be written using instructions which the computer will understand. Computers are very stupid and only understand a limited range of very simple instructions. You must also provide the instructions in exactly the way the computer expects them. Like any receipe, the instructions must obviously be given in the correct order.

The instructions often use some of the less common keyboard symbols in unusual sequences. Do not worry about why this is, just do it that way!

The program instructions are stored in a computer file. You will create and modify this using a `text editor'. On a Windows PC this will usually be the application called Notepad.

Instructions are typed on the keyboard, usually one per line. Upper and lower case letters are NOT the same in most programming languages. Punctuation symbols like , . ; : are NOT interchangable.