[SOLVED] While loop issue

[EchoFool]

I have a while loop which is meant to multiply a number by itself only it gave me a strange ending result...

 

This is what i got:

 

$Level = 10;
		$Check = 0;
		$Power = 1;
		While($Check < $Level){
		$Check = $Check + 1;
		If($Power == 1){
			$Power = $Power + 1;
		}Else{
			$Power = $Power * $Power;
			}




	}
	Echo $Power;

 

And the response is:

1.34078079299E+154

 

Why is that? What did i do wrong.... its meant to loop 10 times. So the $Power should be 1028.. if my maths is correct.

 

Hope you can help.

[Daniel0]

In this case a for loop would be better:

 

$level = 10;
$power = 1;

for($i = 0; $i < $level; $i++)
{
if($power == 1)
{
	$power += 1;
}
else {
	$power *= $power;
}
}

 

Why not just use pow() though?

[EchoFool]

In this case a for loop would be better:

 

$level = 10;
$power = 1;

for($i = 0; $i < $level; $i++)
{
if($power == 1)
{
	$power += 1;
}
else {
	$power *= $power;
}
}

 

Why not just use pow() though?

 

I've never heard of pow() ? What is the $i coming from ? Also what is "$i++" ? Is that just to add 1 to its self?

[revraz]

Also, do the math.

 

The first multiply is 2*2=4

Second is 4*4

Then 16*16

Then 256*256

 

So you are already over 1028 by the 4th round.

[Daniel0]

$i is set by the for loop ($i = 0;). $i++ increments $i with 1 (it's equal to $i += 1 which is similar to $i = $i + 1). pow() is a function for exponential expressions.

 

I.e. you can achieve what you want like this:

$power = pow(2, 10);

[EchoFool]

So $power = pow(2, $level); would also work?

 

I tried your for loop and got:

1.34078079299E+154

 

Which is what i got with my while loop.. what is going wrong ?

[revraz]

You are not doing it right, you want

 

1x1

2x2

3x3

4x4

 

But you are multiplying the result by itself instead.

[EchoFool]

You are not doing it right, you want

 

1x1

2x2

3x3

4x4

 

But you are multiplying the result by itself instead.

 

That won't work cos 1x1 = 1 so if that was the result, then the result in a loop will always end up as 1.

[Daniel0]

I tried your for loop and got:

1.34078079299E+154

 

Which is what i got with my while loop.. what is going wrong ?

That's because I simply wrote the for loop as a replacement for your while loop. The problem still persists with the for loop as explained by revraz. I suppose I should have pointed that out.

 

So $power = pow(2, $level); would also work?

Yes.

[EchoFool]

1 + 1 = 2

2x2 = 4

4x4 = 8

8x8 = 16

 

 

Thats what im aiming to get. Not what revraz showed me. How would i get it to give me a number result not :

1.34078079299E+154

 

Cos i cannot work with 1.34078079299E+154 from that point on, its unusable.

[revraz]

Not sure how much more I can try to explain it.  You are trying to multiply the RESULT by itself, when you need to multiply the step of the LEVEL by itself.

[Daniel0]

8 * 8 ≠ 16

8 * 8 = 64

 

Also, 1.34078079299E+154 is a number (cf. http://en.wikipedia.org/wiki/Scientific_notation#E_notation).

[revraz]

And 4 X 4 = 16, not 8.

 

Do you want the Power or do you want to add them?

[EchoFool]

I am suppose to multiply the result by itself ...not the step of the level...

 

Example:

 

If i multiply the step of the level by the result the numbers are too low...

 

If result is 12044 then it needs to be 12044 X 12044 not:

 

12044 x 8 (as as example of the step of the level).

 

My maths is poor i been mainly thinking in letters whilst making my scripts as formula's represent any numbers.

 

Daniel - Is that still usable as integer in maths etc or will it crash out due to letters and decimal point ?

 

 

[Daniel0]

Daniel - Is that still usable as integer in maths etc or will it crash out due to letters and decimal point ?

 

Take this code for instance:

<?php
echo 1e5;
?>

It will output: 100000

[EchoFool]

Ok is there a way to force :

1.34078079299E+154

 

to come out as a normal huge number ?

 

Like using number_format($power) ?

[Daniel0]

<?php
printf('%.0f', 1.34078079299E+154);
?>

Output: 13407807929900000303292285556480489173702166434470022712912188298402309057064132476718872964460351551886434939009092324761906381094962708370334962038079488

[EchoFool]

Ok thankyou Got it working