PHP实现计算器小功能

本文实例为大家分享了PHP实现计算器小功能的具体代码，供大家参考，具体内容如下

<?php
 if (isset($_POST[\'sub\'])) {
 $f = true;
 $error = \"有以上问题: <br>\";
 if ($_POST[\"num1\"] == \"\") {
  $f = false;
  $error .= \"第一个数不能为空.<br>\";
 } else {
   if(!is_numeric($_POST[num1])) {
    $f = false;
    $error .= \"第一个数字不是数字.<br>\";
   }
 }
 if ($_POST[\'num2\'] == \"\") {
  $f = false;
  $error .= \"第二个数字不能为空.<br>\";
 } else {
   if (!is_numeric($_POST[\'num2\'])) {
   $f = false;
   $error .= \"第二个数字不是数字<br>\";
  }
 }
 if ($f) {
  switch ($_POST[\'ysf\']) {
  case \'+\': $sum = $_POST[\'num1\']+$_POST[\'num2\'];
   break;
  case \'-\': $sum = $_POST[\'num1\']-$_POST[\'num2\'];
   break;
  case \'*\': $sum = $_POST[\'num1\']*$_POST[\'num2\'];
   break;
  case \'/\': $sum = $_POST[\'num1\']/$_POST[\'num2\'];
   break;
  case \'%\': $sum = $_POST[\'num1\']%$_POST[\'num2\'];
   break;
  }
 }
 }
?>

<!doctype html>
<html>
<head>
<meta charset=\"utf-8\">
<title>简易计算器</title>
<style>
 * {
  margin: 0px;
 padding: 0px;
 }
 #contains {
  width: 400px;
 margin: 50px auto;
 }
 h1 {
  width: 400px;
 text-align: center;
 color: #0F0;
 }
 table {
  margin-top: 20px;
 width: 400px;
 }
 input {
  background: yellow;
 border-radius: 20px;
 }
 input:hover {
  background: green;
 }
 select {
  background: yellow;
 border-radius: 20px;
 }
 td {
  background: #3F0;
 text-align: center;
 height: 30px;
 }
 #sub {
  border-radius: 25px;
 width: 50px;
 }
</style>
</head>
 
<body>
 <div id=\"contains\">
  <h1>简易计算器</h1>
 <form action=\"Calculator.php\" method=\"post\">
 <table border=\"0\">
  <tr>
  <td><input type=\"text\" name=\"num1\" value=\"<?php echo $_POST[\'num1\'];?>\" size=\"3\"/></td>
  <td>
   <select name=\"ysf\">
   <option <?php if($_POST[\'ysf\'] == \"+\") echo \"selected\";?> value=\"+\">+</option>
   <option <?php if($_POST[\'ysf\'] == \"-\") echo \"selected\";?> value=\"-\">-</option>
   <option <?php if($_POST[\'ysf\'] == \"*\") echo \"selected\";?> value=\"*\">*</option>
   <option <?php if($_POST[\'ysf\'] == \"/\") echo \"selected\";?> value=\"/\">/</option>
   <option <?php if($_POST[\'ysf\'] == \"%\") echo \"selected\";?> value=\"%\">%</option>
   </select>
  </td>
  <td><input type=\"text\" name=\"num2\" value=\"<?php echo $_POST[\'num2\'];?>\" size=\"3\"/></td>
  <td><input type=\"submit\" id = \'sub\' name=\"sub\" value=\"计算\"/></td>
  </tr>
  <tr>
   <td colspan=\"4\">
   <?php
    if ($f) {
    echo \"计算结果: <b>{$_POST[\'num1\']}{$_POST[\'ysf\']}{$_POST[\'num2\']} = {$sum}</b>\";
   } else {
    echo \"<b>$error</b>\";
   }
   ?>
  </td>
  </tr>
 </table>
 </form>
 </div>
</body>
</html>