I'm going to show you some other loops that I prefer

when it comes to looping through arrays.

But I don't want you to think that while loops are unimportant.

Let's create a simple ping pong game to demonstrate another use case for

while loops.

Let's create a new file named pingpong.php We add our PHP tags.

And then we're ready to start programming the game.

We'll start with two players, each with an initial score of 0.

$player1 = 0.

And $player2 = 0.

I also want to track how many rounds each game takes.

So I'm going to add another variable.

$round = 0.

Now let's add some comments.

To win, a player must reach the score of 11.

While also being a minimum of 2 points higher than their opponent.

So while those conditions are not met.

I'm going to randomly increment one of the player's scores each round.

To check for the difference between the player scores,

I can subtract one score from the other.

This will give me a number that can be positive or

negative depending on which score is higher.

We can then find the absolute value of that number.

Let me demonstrate.

Let's change $player2 = 5.

Then we'll do a var_dump.

$player1- $player2.

Then we'll also var dump $player2- $player1.

Let's run the script.

I see that the first var dump shows -5 and this the second var dump shows 5.

The difference between these numbers is 5.

All I care about is that the difference between these numbers is greater than 2.

I don't care which is the higher number.

So, I can use a function to determine the absolute value, abs.

I'll add this to the first var_dump.

Now, when I run my script.

You can see that the absolute value gives me the number itself,

without the negation before it.

I can use this absolute value in my while loop.

Let’s comment out these var dumps.

So I want to continue to loop while the absolute value is less than 2.

I also want to continue to loop while both scores are less than 11.

So I'm going to add a second expression.

I’ll combine these with the double pipe

operator because I want either or to be true.

$player1 is less than 11 and

$player2 is less than 11.

I need to put parenthesis around these two expressions so

that they evaluate as a single conditional.

$player1 must be less than 11 and

$player2 must be less than 11 to continue my loop.

So if the difference between the players is less than 2, we'll continue to loop.

Or if $player1 and $player2 are both less than 11 we will continue to loop.

The first thing I want to do is to start incrementing the round.

This would be round 1.

So adding 1 to 0 = 1.

Let's also let the user know what's going on with each loop.

So let's start with the heading for the round.

I want to view this in the browser, so let's add the HTML tags.

Round $round, And close my tags.

Notice that I used the double quote, so that my variable is expanded.

Now we want to randomly add a point to either $player1 or $player2.

PHP has a function named RAND that will generate a random integer.

We can specify a minimum and a maximum for this random integer.

So we can say if {rand(0,1)

then we're going to do something.

The min and max are inclusive, meaning it will include the minimum and

the maximum in its random number generation.

With a minimum of 0 and a maximum of 1,

we will randomly receive either 0 or 1.

Since 0 evaluates to false and 1 evaluates to true,

we can use this in our conditional.

If 1 is returned and our expression is true, we can add 1 to $player1.

Else we can add 1 to $player2.

Now, let's display the current score for this round.

Player1 = $player1 score and a line break

Player2 = $player2 score and a line break.

And that's all we need for a while loop.

So let's preview this script in a browser.

We can see each round with a point being awarded to a random player.

And the final score ending with Player1 = 2 and Player2 having 11.

This is okay, but let's add a final summary.

After our while loop, we should add our comment back up in the while loop.

And after our comment we can add echo header 1.

If $player1 > $player2,

we'll echo Player1.

Else we'll echo Player2.

And finally we'll echo,

is the winner after $round rounds.

And close our header.

Let's preview our script again to see the final result.

Player 2 is the winner after 9 rounds.