Basic questing involving array

[ParkingLot]

I have this set of code here out of my text book that i'm working with. I understand how all the code works except for one part that i'm not to sure what it's doing. The part that confuses me is in the if statement for example the $FaceNamesPlural[$Die1-1] the part that stumps me is the [$Die1-1] not really understanding what the -1 part is doing my only guess is that it's maybe pulling the element thats index is 1 in the array? Thanks for any feedback.

 

 

<?php

 

$FaceNamesSingular = array("one", "two", "three", "four", "five", "six");

$FaceNamesPlural = array("ones", "twos", "threes", "fours", "fives", "sixes");

 

 

 

function CheckForDoubles($Die1, $Die2)

{

global $FaceNamesSingular;

global $FaceNamesPlural;

 

if ($Die1 == $Die2) //Doubles

echo "The roll was double ", $FaceNamesPlural[$Die1-1], ".<br>";

 

if ($Die1 != $Die2) //not Doubles

echo "The toll was a ", $FaceNamesSingular[$Die1-1], " and a ", $FaceNamesSingular[$Die2-1], ".<br>";

}

 

 

 

function DisplayScoreText($Score)

{

if ($Score == 2)

echo "You rolled snake eyes!<br>";

if ($Score == 3)

echo "You rolled a loose deuce!<br>";

if ($Score == 5)

echo "You rolled a fever five!<br>";

if ($Score == 7)

echo "You rolled a natural!<br>";

if ($Score == 9)

echo "You rolled a nina!<br>";

if ($Score == 11)

echo "You rolled a yo!<br>";

if ($Score == 12)

echo "You rolled boxcars!<br>";

 

}

 

$Dice = array();

$Dice[0] = rand(1,6);

$Dice[1] = rand(1,6);

$Score = $Dice[0] + $Dice[1];

echo "<p>";

echo "The total score for the roll was $Score. <br>";

 

checkForDoubles($Dice[0], $Dice[1]);

DisplayScoreText($Score);

echo "</p>";

 

 

 

 

?>

[Jessica]

It's compensating for the fact that array keys start at 0.

[ParkingLot]

I understand that the array's start at [0][1][2] i'm just not sure what this part is exactly doing >> [$Die1-1] <<

Edited January 27, 2013 by ParkingLot

[Jessica]

What dice name is at key #2? Is that what you want to echo for rolling a 2?

[kicken]

I understand that the array's start at [0][1][2] i'm just not sure what this part is exactly doing >> [$Die1-1] <<

 

It's just math.  For example, if $Die1 is currently set to 6 then $Die1-1 is 6-1 which equals 5.

 

Then it looks up index 5 in the given array, ie $FaceNamesPlural[5] which would be 'sixes'

Edited January 27, 2013 by kicken

[ParkingLot]

It's just math. For example, if $Die1 is currently set to 6 then $Die1-1 is 6-1 which equals 5.

 

Then it looks up index 5 in the given array, ie $FaceNamesPlural[5] which would be 'sixes'

 

Thanks I understand it now!