Hour of Code - Bill Gates explains If statements

People make decisions every day.

For example before you go outside

you kind of have an IF statement that says,

IF it's raining,
THEN I need to get my jacket.

And, computers are amazing once you decide those kinds of statements,

that they can reliably execute those things at unbelievable speed.

And so, a computer program really

is a little bit of math and some

IF statements, where the decision gets made.

So, in this puzzle the

IF block helps the zombie make a decision,

it checks something.

For example let's use the block that says, "if there's a path to the left,"

and put a "turn left" command inside it.

So, we're telling the zombie to check its surroundings,

see if there's that path on the left,

and if so, make that turn.

And then we use the "move forward" block inside this "repeat"

to get it to keep moving forward as long as

it just wants to go straight.

Then when there's the turn, the IF block
will tell it to make this turn to the left.

And you can see, if we do that

if we're taking the turn to the left and otherwise moving forward,
we'll achieve our goal.

So it's an example of using an IF statement,

which is really a fundamental concept in computer programming.

One of the first things I learned was how to write a program to play tic-tac-toe.

So I had IF statements to say okay,

IF the other person is about to win go ahead and block that spot.

So have fun learning how to use IF statements. It's a key concept.