View Category

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) );

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);
echo round(7/8, 2);

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);
}