07c04-1.php

介绍PHP5的给类型函数应用

<?php
// Define a Math class that provides static and const members for use
class Math_Extended {
    // Declare some constant variables for reference:
    // Speed of light (meters per second) (exact)
    const C = 299792458;

    // Temperature of the Sun (Kelvin) (approximate)
    const T_SUN = 5780;
    
    // Radius of the Earth (meters) (approximate)
    const R_EARTH = 6378000;
    
    // Now let's declare some static methods - Start with a cube root one:
    public static function curt($num) {
        return pow($num, 1/3);
    }
    
    // A method that will generate the length of a side of a right-angle
    // triangle, given the length of one side, and of the hypotenuse
    public static function triSide($hypot, $side) {
        return sqrt(pow($hypot, 2) - pow($side, 2));
    }
}

// See how long it takes for light to traverse the diameter of the Earth
$seconds = (Math_Extended::R_EARTH * 2) / Math_Extended::C;
echo "<p>The light would take {$seconds} seconds</p>\n";

// Calculate the side of a right triangle.  Use a 1,2,sqrt(3) triangle
$side = Math_Extended::triSide(2, sqrt(3));
echo "<p>The other side of the triangle is {$side}</p>\n";

// Calculate the cube root of 27
$root = Math_Extended::curt(27);
echo "<p>The cube root of 27 is {$root}</p>\n";
?>