I'm trying to use php code to print out pascals triangle (in the diagonal style like this- http://www.cut-the-knot.org/arithmetic/combinatorics/PascalTriangle.gif)
I tried this code:
<?php
$f = 10;
for ($x = 0; $x <= $f; $x++) {
echo "1"." ";
$previous_line[$x]=1;
}
echo "<br>";
for ($x = 0; $x < $f; $x++) {
echo "1"." ";
for ($y = 1; $y <= $f-$x-1; $y++) {
$sum = 0;
for ($z = 0; $z <= $y; $z++) {
$sum = $sum + $previous_line[$z];
}
echo $sum." ";
}
echo "<br>";
}
But I get this output:
1 1 1 1 1 1 1 1 1 1 1
1 2 3 4 5 6 7 8 9 10
1 2 3 4 5 6 7 8 9
1 2 3 4 5 6 7 8
1 2 3 4 5 6 7
1 2 3 4 5 6
1 2 3 4 5
1 2 3 4
1 2 3
1 2
1
What am I doing wrong?
I think you use same $previous_line[$] value for every line, so the the iteration value of $sum will increased constantly. (increased by 1)
You should update $previous_line[$] value on every line:
$previous_line[$y] = $sum;
and you don't need to use this iteration:
for ($z = 0; $z <= $y; $z++) {....}
This is full code:
<?php
$f = 10;
for ($x = 0; $x <= $f; $x++) {
echo "1"." ";
$previous_line[$x]=1;
}
echo "<br>";
for ($x = 0; $x < $f; $x++) {
$sum = 1;
echo $sum." ";
for ($y = 1; $y <= $f-$x-1; $y++) {
$sum = $sum + $previous_line[$y];
echo $sum." ";
$previous_line[$y] = $sum;
}
echo "<br>";
}
Just try it
Since Justin beat me to the punch, I though I would post an improved version.
Please note that there is probably better ways to do this.
I removed your first loop since it wasn't need, then I moved $previous_line inside the second loop and checked to make sure that it is being set. Last I update $currentSum and assign
$totalToLoop = 10;
for ($x = 0; $x <= $totalToLoop; $x++) {
$currentSum = 1;
echo '1 ';
for ($y = 1; $y <= ($totalToLoop - $x); $y++) {
if (!isset($previous_line[$y])) {
$previous_line[$y] = 0;
}
printf('%d ', $currentSum = ($currentSum + $previous_line[$y]));
$previous_line[$y] = $currentSum;
}
echo '<br>';
}
results.
1 1 1 1 1 1 1 1 1 1 1
1 2 3 4 5 6 7 8 9 10
1 3 6 10 15 21 28 36 45
1 4 10 20 35 56 84 120
1 5 15 35 70 126 210
1 6 21 56 126 252
1 7 28 84 210
1 8 36 120
1 9 45
1 10
1
Related
I am trying to use this chunk of code as template, but Im not fully understanding of how one line works. I'll first provide the full chunk, then I'll single out the line I don't understand.
/** settings **/
$images_dir = 'preload-images/';
$thumbs_dir = 'preload-images-thumbs/';
$thumbs_width = 200;
$images_per_row = 3;
/** generate photo gallery **/
$image_files = get_files($images_dir);
if(count($image_files)) {
$index = 0;
foreach($image_files as $index=>$file) {
$index++;
$thumbnail_image = $thumbs_dir.$file;
if(!file_exists($thumbnail_image)) {
$extension = get_file_extension($thumbnail_image);
if($extension) {
make_thumb($images_dir.$file,$thumbnail_image,$thumbs_width);
}
}
echo '<img src="',$thumbnail_image,'" />';
if($index % $images_per_row == 0) { echo '<div class="clear"></div>'; }
}
echo '<div class="clear"></div>';
}
else {
echo '<p>There are no images in this gallery.</p>';
}
I understand how everything with the exception of this line works.
if($index % $images_per_row == 0) { echo '<div class="clear"></div>'; }
I know it is getting its value from this line:
$images_per_row = 3;
But what actually makes this work? Im still pretty new to php, and I would like a better understanding of the code Im about to use before I use it.
Any answers at all would be appreciative!
$index % $images_per_row == 0
The % means "mod", example 4 mod 2 = 0.
A % B = the remainder when we divide A by B.
In your script, the condition is met (valued to 'true') when the remainder of $index divided by $images_per_row equals 0, meaning the divisibility of $index by $images_per_row.
Hope it helps!
% is the modulo operator. It divides the two numbers and then returns the remainder after the division.
It is quite easy to understand if you remember your fractions and how to reduce them to their lowest terms.
So, if we make 5 % 2 into a fraction and reduce it:
5 1 (this is the remainder)
--- → 2 ---
2 2
So, 5 % 2 = 1.
If we take 8 % 3 we can do the same thing:
8 2 (this is the remainder)
--- → 2 ---
3 3
So, 8 % 3 = 2.
If there is no remainder, such as in 9 % 3 then you will get 0 back. See:
9 0 (this is the remainder)
--- → 3 ---
3 3
You can write some PHP to see what the values are when doing the modulo operations:
$perRow = 3;
for ($i = 0; $i < 10; $i++) {
echo "$i % $perRow = ", $i % $perRow, ' | ', "$i / $perRow = ", ($i / $perRow), "\n";
}
Output:
0 % 3 = 0 | 0 / 3 = 0
1 % 3 = 1 | 1 / 3 = 0.33333333333333
2 % 3 = 2 | 2 / 3 = 0.66666666666667
3 % 3 = 0 | 3 / 3 = 1
4 % 3 = 1 | 4 / 3 = 1.3333333333333
5 % 3 = 2 | 5 / 3 = 1.6666666666667
6 % 3 = 0 | 6 / 3 = 2
7 % 3 = 1 | 7 / 3 = 2.3333333333333
8 % 3 = 2 | 8 / 3 = 2.6666666666667
9 % 3 = 0 | 9 / 3 = 3
I want this output:
1 1 1 1 1 1
2 2 2 3 3 3
4 4 5 5 6 6
7 8 9 10 11 12
I think I need to three nested For(), But I don't know how should I print the above result. Here is my code, How to complete it? (though I don't know, maybe my code is completely wrong)
for ($i=1; $i<=4; $i++) // row
{
for ($j=1; $j<=6; $j++) // column
{
for($z=1; $z<=12; $z++) // number
{
// what should be in here?
}
}
}
Edit: I want something like these examples: (Although these examples are very simple, what I want is a little more harder)
for ($i=1; $i<=4; $i++)
{
for ($j=1; $j<=6; $j++)
{
echo $i.' ';
}
echo '<br>';
}
1 1 1 1 1 1
2 2 2 2 2 2
3 3 3 3 3 3
4 4 4 4 4 4
Or this: echo $j;
1 2 3 4 5 6
1 2 3 4 5 6
1 2 3 4 5 6
1 2 3 4 5 6
Edit2:
Note: I need to a code that be able to print this either: (its logic is the same with first output)
4 4 4 4 4 4
5 5 5 6 6 6
7 7 8 8 9 9
10 11 12 13 14 15
You can try something like this.
var $c = 1;
for ($i=1; $i<=4; $i++)
{
var $noOfChanges = 6/$i;
for ($j=1; $j<=6; $j++)
{
echo $c.' ';
if($j%$noOfChanges==0){
$c = $c + 1;
}
}
echo '<br>';
}
Not tested.
You can intialize the var $c = 4; to get the next pattern.
Tested and working:
$length = 6;
$row = 0;
$number = 1;
$total = 0;
$n = $length;
while(true) {
$n = floor($length/($row+1));
for($i = 0; $i<$n; $i++) {
echo $number;
echo "\t";
}
$total+=$n;
if($total >= $length) {
$row++;
$total = 0;
echo "\n";
if($n == 1 ) break;
}
$number++;
}
Output:
3
3 4
3 4 5
3 4 5 6
3 4 5 6 7
3 4 5 6 7 8
function Triangle ($begin, $end) {
if ($begin < 0 || $end < 0) {
return;
}
if ($begin == $end) {
return $a;
}
else {
// non recursive
for ($i = 1; $i <= $end; $i++) {
for ($j = $begin; $j <= $i; $j++) {
echo $j . " ";
}
echo "<br>";
}
}
}
This is what I made so far.
Here's one way:
function triangle ($begin, $end, $row = 1) {
//stop when we've printed up to end
if($end - $begin + 1 < $row) return;
//let's start at the beginning :)
for($i = 0; $i < $row; $i++){
//the row number increments each time so we can keep adding.
echo ($begin + $i)." ";
}
echo "<br>";
//now recurse...
triangle($begin, $end, $row + 1);
}
Usage:
triangle(3,9);
Output:
3
3 4
3 4 5
3 4 5 6
3 4 5 6 7
3 4 5 6 7 8
3 4 5 6 7 8 9
This should work for you:
(Here I just added the variable step which defines how many steps you make from $begin to $end and if $begin + $step == $end the function is done. If not It starts from $begin and makes X steps and as long as it doesn't reach the end I call the function again with a step more)
<?php
function Triangle($begin, $end, $step = 0) {
for($count = $begin; $count <= ($begin+$step); $count++)
echo "$count ";
echo "<br />";
if(($begin + $step) == $end)
return;
else
Triangle($begin, $end, ++$step);
}
Triangle(3, 8);
?>
output:
3
3 4
3 4 5
3 4 5 6
3 4 5 6 7
3 4 5 6 7 8
Hi I'm Learning php and trying to do a for loop look like this wtih this code:
for($x=1; $x<=20; $x++){
echo $x;
$x = $x + 3; //5
echo "<br/>";
}
It's produce
1
5
9
13
14
But I want it should be...
1
5
10
15
20
for ($x = 0; $x <= 20; $x += 5) {
echo ($x == 0 ? 1 : $x), '<br>';
}
Or:
foreach (range(0, 20, 5) as $x) {
echo ($x == 0 ? 1 : $x), '<br>';
}
You can't produce the sequence without 1 extra condition because the delta differs in the first step:
1 + 4 ...
5 + 5
10 + 5
15 + 5
20 + 5
there are more than one solution.
one is:
for($x=1; $x<=20; $x++){
if(!($x % 5) || $x==1)
echo $x . "<br />";
}
Explination
% is the modulo operator. It returns the devision rest.
lets say $x is 3 than 3 % 5 would return 3 because the result 3/5 = 0 rest 3
if its $x is 10, it return 0. 10/5 = 2 rest 0
In the if-statement I use !-not operator. This turns around the result.
Because if takes 1+ (one and more) as true and 0- (zero and less) as false
So rest of 3 would be positiv (true) but in this case i want it to be false. So I turn arount the true/false with !
% - Modulo
R - Rest
1 % 5 = 0 R 1 // would say true to if
2 % 5 = 0 R 2 // would say true to if
3 % 5 = 0 R 3 // would say true to if
4 % 5 = 0 R 4 // would say true to if
5 % 5 = 1 R 0 // would say false to if
6 % 5 = 1 R 1 // would say true to if
and so on...
try this.
$x = 1;
for ($j = 1; $j <= 20; $j++) {
echo $x, "<br/>";
if ($x == 1) {
$x = $x + 4;
} else {
$x = $x + 5;
if($x > 20){break;}
}
}
if this answer is work for you please mark the answer.
Try this:
for($x=1; $x<=20; $x++) {
if($x%5==0 || $x==1) {
echo $x;
echo "<br>";
}
}
I need to display array of 10 numbers in three columns. if i add another number some like, 11 it must add below 10. as numbers increasing row can be increased not the column, can any one say?
1 4 7 10
2 5 8
3 6 9
am getting 10 in fourth column, but i need it in third column. and row will get increased like
1 4 8
2 5 9
3 6 10
4 7
Display Output in table..
<?php
$arr = array("1","2","3","4","5","6","7","8","9","10", "11", "12", "13");
$row= ceil(count($arr)/3);
echo "<table border='1'>";
for($i = 1; $i <= $row; $i++) {
echo "<tr>";
echo "<td>". $i ."</td>";
$k = 0;
$pre = 0;
for($j = 1; $j <= 2; $j++) {
if($pre == 0)
$pre = $k = $i + $row;
else
$pre = $pre + $row;
if($pre <= max($arr))
echo "<td>". $arr[$pre-1] ."</td>";
}
echo "</tr>";
}
echo "</table>";
?>
Output will be:
1 6 11
2 7 12
3 8 13
4 9
5 10
Try this...
<?php
$arr = array("1","2","3","4","5","6","7","8","9","10", "11", "12", "13", "14");
$row= ceil(count($arr)/3);
for($i = 1; $i <= $row; $i++) {
echo $i;
$k = 0;
$pre = 0;
for($j = 1; $j <= 2; $j++) {
if($pre == 0)
$pre = $k = $i + $row;
else
$pre = $pre + $row;
if($pre <= max($arr))
echo " ". $arr[$pre-1] ." ";
}
echo "<br>";
}
?>
Output when 14 element:
1 6 11
2 7 12
3 8 13
4 9 14
5 10
Output when 11 element:
1 5 9
2 6 10
3 7 11
4 8
Output when 13 element:
1 6 11
2 7 12
3 8 13
4 9
5 10