If Statements

If statements are a basic part of every programming language. The idea is that they allow you to test a condition and then perform an action if the test passed.

This might sound like a very simple idea, but it’s a simple idea that has a lot of very grand implications. If you think about it, every single decision follows the same structure. If your sandwich is sitting in front of you, you go through a series of checks to decide whether or not to eat it, “If I am hungry, then I will eat the sandwich.” “If I like the sandwich ingredients, then I will eat the sandwich.” (It’s good to stop at this point and each the sandwich. Otherwise you may get lost in the process of figuring out if you’ve done your if-then structure for every decision aspect you needed to).

Let’s look at a really simple example and then we’ll look at a more interesting example.

In this example we are testing if an integer i is equal to 0. If it is, we print out the fact that it is zero. Pretty simple, eh? As promised, here’s a more interesting example.

In this example, we are using two methods not shown, one validates that a user ID exists and the other validates that the password entered for that ID is correct. If both of those return true, we give the user access to the system.

Why should you care?

Have you ever played against a computer chess program and felt like it was intelligent? Or seen a chat bot that for a second, seemed to be really answering your questions? At some level those things and others are powered by if statements. The ability to perform an action based on criteria is the first step in taking a computer from being a machine with consistent input and output to being a device that may seem to think and react to you. Not to sound too grandiose, but it’s the first step into the magical world of programming.