A program loop question....which color wins?

Hi:

can anyone please explain how many times does the following program loop? Please list the values of $move and $color at the end of each loop, and explain each result if possible. Thank you.



<?php
$move = 0;
$color = "red";
$turns = 0;
while ($move <= 10) {
if ($turns > 100) {
#oops, infinite loop!
echo "Abort!";
break;
}
else if ($move < 4 && $move <> 2) {
$move += 3;
$color = "green";
}
else if ($move == 8 AND $color == "red") {
$move--;
$color = "yellow";
}
else if ($color == "yellow" XOR $move >= 7) {
$move++;
$color = "blue";
}
else {
$move += 2;
$color = "red";
}
$turns++;
}
?>

 

First value of $move is 0, so condition ($move < 4 && $move <> 2) is true, second it's 3 (value added in this if-else), then it's become 6 that not satisfy any condition, so it goes to last else, where it's become 8, now it satisfy ($color == "yellow" XOR $move >= 7)...

Simply, add at the end of loop:
echo "Loop nr.$turns, \$move $move, \$color $color\n";

You got:
Loop nr.1, $move 3, $color green
Loop nr.2, $move 6, $color green
Loop nr.3, $move 8, $color red
Loop nr.4, $move 7, $color yellow
Loop nr.5, $move 9, $color red
Loop nr.6, $move 10, $color blue
Loop nr.7, $move 11, $color blue

 

Sorry, still not very clear.

while ($move <= 10) {
if ($turns > 100) {
#oops, infinite loop!
echo "Abort!";
break;
}

for the above part, we get $move = 0, is that right? because $turns is not larger than 100, it is 0.

else if ($move < 4 && $move <> 2) {
$move += 3;
$color = "green";
}

for the above part, because $move = 0, now 0+3 = 3, is that right? up to this point, $move = 3 and color = "green" ?

so how come it then becomes 6? I am lost after this. Please explain more, thank you.

 

While condition ($move <= 10) is true the operation repeats. So, the increment repeats, initially $move becomes 3, then second once it becomes 6.

Look en.wikipedia.org/wiki/while_loop for more details.

 

Kind of understand.

Can you give an example showing how to change the conditional statements only to make a different color wins?

By the way, XOR means to execute the function if the value does not match the condition? so if color is yellow, or move>=7, do not execute?

else if ($color == "yellow" XOR $move >= 7) {
$move++;
$color = "blue";
}



Thank you