Getting feedback is tough. Just look at J.K. Rowling's list of rejections. Sometimes you just have to send something in, hope for the best, and hunker down in your positivity bunker when the truth bomb hits. Feedback from computers doesn't usually have those kinds of odds. In fact, they're usually pretty fast about giving you output.

Assuming you gave them good input, of course.

In computer terms, input can be called the information or data a program needs in order to operate. To give it that info, you'll need to use an input device like a keyboard, a mouse, microphone, camera, disk, or jump drive. Any one of these is literally designed to give your computer the information it needs to run.

Besides all those physical gizmos, you can create more input any time you

• type a command.
• open a file.
• click on a button.
• enter an address or URL.

Once the computer's done computing things (with a lot of whirring and boinging to make you know it's still going strong), it's going to send some output your way, in the form of

• an image on the monitor.
• a song through the speakers. 
• a printed page from…the printer.

Say you're building a trap for the squirrel that keeps getting into your birdfeeder. To figure out how to build this thing, you download an app for your phone (SquirrelAway) to help figure out the best squirrel trap for you. Before it can compute the statistically strongest squirrel guard, you're going to need to throw in some input like the size of your birdfeeder, the size of the squirrel, and the amount of money you're willing to fork over to make that squirrel an offer it can't refuse.

(Without a budget, you could probably use heat-sensing lasers or something.)

Once your computer goes through its complex, squirrel-hating algorithm, it's going to output the best defense against squirrels your money can buy.

Now you're one step closer to the bird haven of your dreams.