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Find the distance between two points
php
$distance = sqrt( pow(($x2 - $x1), 2) + pow(($y2 - $y1),2) );
class Point2D {
var $x;
var $y;
function __construct($x, $y) {
$this->x = $x;
$this->y = $y;
}
}
$a = new Point2D($x1,$y1);
$b = new Point2D($x2,$y2);
$distance = sqrt( pow(($b->x - $a->x), 2) + pow(($b->y - $a->y),2) );
var $x;
var $y;
function __construct($x, $y) {
$this->x = $x;
$this->y = $y;
}
}
$a = new Point2D($x1,$y1);
$b = new Point2D($x2,$y2);
$distance = sqrt( pow(($b->x - $a->x), 2) + pow(($b->y - $a->y),2) );
Zero pad a number
Given the number 42, pad it to 8 characters like 00000042
php
echo str_pad(42, 8, 0, STR_PAD_LEFT);
printf("%08d", 42);
Right Space pad a number
Given the number 1024 right pad it to 6 characters
"1024 "
php
echo str_pad(1024, 6, " ");
printf("%s ", 1024);
Format a decimal number
Format the number 7/8 as a decimal with 2 places: 0.88
php
printf("%.2g", 7/8);
Left Space pad a number
Given the number 73 left pad it to 10 characters
" 73"
php
echo str_pad(73, 10, " ", STR_PAD_LEFT);
printf("%10d", 73);
Generate a random integer in a given range
Produce a random integer between 100 and 200 inclusive
php
$r = mt_rand(100, 200);
Generate a repeatable random number sequence
Initialise a random number generator with a seed and generate five decimal values. Reset the seed and produce the same values.
php
mt_srand(9876);
$r1 = array();
foreach(range(1,5) as $i) {
$r1[$i] = mt_rand(1,100);
}
mt_srand(9876);
$r2 = array();
foreach(range(1,5) as $i) {
$r2[$i] = mt_rand(1,100);
}
$r1 = array();
foreach(range(1,5) as $i) {
$r1[$i] = mt_rand(1,100);
}
mt_srand(9876);
$r2 = array();
foreach(range(1,5) as $i) {
$r2[$i] = mt_rand(1,100);
}
