PHP implementation of simple triangles, rectangular perimeter area calculator sharing _php instance

Using the object-oriented knowledge of PHP to design a graphics calculator, but also the use of abstract knowledge, the calculator can calculate the circumference and area of the triangle, as well as the circumference and area of the rectangle. This graphics Calculator has 4 pages: 1.    PHP Graphics Calculator Home index.php;    2. Abstract class shape.class.php of shape;    3 triangular calculation class triangle.class.php; 4. Rectangular calculation class rect.class.php.

PHP Graphics Calculator Code Click to download: PHP graphics calculator. zip

The code is as follows:

PHP Graphics Calculator Home:

Abstract class for shapes:

The abstract class shape{
//shape name is public
$name;
The calculated area method of the shape
abstract function areas ();
The method of calculating the circumference of a shape
abstract function Zhou ();
Shape graphic Form Interface
abstract function view ();
The validation method of the shape
abstract function yan ($arr);

Triangle Compute class File:

Class Triangle extends Shape {    private $bian 1;     private $bian 2;  &
Nbsp;  private $bian 3;       function __construct ($arr = Array ()) {         if (!empty ($arr)) {             $this->bian1
= $arr [' Bian1 '];
             $this->bian2 = $arr [' bian2 '];
             $this->bian3 = $arr [' bian3 '];           }           $
This->name = "triangle";    &NBSP}       function area () {      
   $p =    ($this->bian1 + $this->bian2 + $this->bian3)/2;           reTurn sqrt ($p * ($p-$this->bian1) * ($p-$this->bian2) * ($p-$this->bian3));    &NBSP}       function Zhou () {      
  return $this->bian1 + $this->bian2 + $this->bian3;    &NBSP}       function view () {      
   $form = ' <form action= ' index.php?action=triangle ' method= ' post ' > ';          $form. = $this->name. ' First side: <input type= "text" Name= "Bian1"
Value= "'. $_post[' Bian1 ']. '/><br> ';          $form. = $this->name. ' Second edge: <input type= "text" Name= "Bian2"
Value= "'. $_post[' bian2 ']. '/><br> ';          $form. = $this->name. ' Third side: <input type= "text" Name= "BIAN3"
Value= "'. $_post[' bian3 ']. '/><br> ';          $form. = ' <inpuT type= "submit" Name= "dosubmit" value= "calculated" ><br> ";
         $form. = ' <form> ';
        echo $form; &NBSP;&NBSP;&NBSP;&NBSP}       function Yan ($arr) {      
   $BJ = true;         if ($arr [' Bian1 '] < 0) {      
      echo "The first side can not be less than 0!<br>";
             $BJ = false; &NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP}           if ($arr [' bian2 '] < 0) {            echo] The second edge cannot be less than 0!<br
> ";
             $BJ = false; &NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP}   &NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;   if ($arr [' bian3 '] < 0) {            
echo "Third edge cannot be less than 0!<br>";
             $BJ = false; &NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP}           if ($ arr[' bian1 ']+ $arr [' bian2 '] < $arr [' bian3 ']) | | ($arr [' bian1 '] + $arr [' bian3 '] < $arr [' bian2 ']) | | ($arr [' bian2 ']+ $arr [' bian3 '] < $arr [' Bian1 ']) {            echo "The sum of both sides must be greater than the third side";    
          $BJ = false; &NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP}           return $ 
bj &NBSP;&NBSP;&NBSP;&NBSP}}

rectangular Computed class file:

Class Rect extends Shape {    private $width;     private $height;   &NBSP ;    function __construct ($arr =array ()) {          if ( !empty ($arr)) {             $this->width = $arr ['
Width '];
             $this->height = $arr [' height '];        &NBSP}          $this->
Name = "Rectangle";    &NBSP}       function area () {      
  return $this->width * $this->height;    &NBSP}       function Zhou () {      
  return 2* ($this->width + $this->height); &NBSP;&NBSP;&NBSP;&NBSP}       function view () {         $form = ' <form action= ' index.php?action=rect ' method= ' post ' > ';          $form. = $this->name. ' Wide: <input type= "text" name= "width"
Value= "'. $_post[' width ']. '/><br> ';          $form. = $this->name. ' High: <input type= "text" name= "height"
Value= "'. $_post[' height ']. '/><br> ';          $form. = ' <input type= "submit" Name= "Dosubmit" value= "calculation" >
<br> ';
         $form. = ' <form> ';
        echo $form; &NBSP;&NBSP;&NBSP;&NBSP}       function Yan ($arr) {      
   $BG = true;         if ($arr [' width '] < 0) {             echo $this->name. " The width cannot be less than 0!&Lt;br> ";              $BG = false;      &NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP}           if ($arr [' Height '] < 0 {            echo $this->name. "
The height can not be less than 0!<br> ";
             $BG = false; &NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP}           return $
Bg &NBSP;&NBSP;&NBSP;&NBSP}  }