26.3 Design Principles

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There are a couple of basic design principles you should keep in mind when creating your design. They will help you create a design that not only works, but is robust and elegant.

The first is "Think, then code." Far too many people, when given an assignment, can't wait to start coding. But the good programmers spend some time understanding the problem and studying all aspects of it before they start coding. After all, if you are driving from San Diego to Chicago, do you jump in the car and head north-east, hoping you'll get there, or do you get out a map and plan your route? It's a lot less trouble if you plan things before you start doing.

Following Orders

One of my favorite movies is called The King of Hearts . It is set in World War I. My favorite scene is where the general is giving three commandos their orders. This trio is a crack unit, well-known for instantly following orders.

"Men," begins the General, "I want you to leave right away."

The three turn around and run off.

"Stop" shouts the General. They halt and turn around. "Where do you think you're going?"

"No idea, sir," they answer in unison .

Far too many programmers act like these commandos. They run off and start typing on the keyboard before they have an idea where they are going.

The other design principle is "be lazy" (a.k.a efficient). The easiest code you'll ever have to implement and debug is the code that you designed out of existence. The less you do, the less that can go wrong. You'll also find that your programs are much simpler and more reliable.

Design Guideline: Think about a problem before you try to solve it.

Design Guideline: Be as efficient and economical as possible.

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