简易计算器

<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <title>计算机</title>
  </head>
  <body>
    <h1>计算器</h1>
    <h2></h2>
    <hr />
    <br />
    <form  action="#" method="post">
      <input type="number" name="num1" >
      <select name="pt">
        <option value="+">+</option>
        <option value="-">-</option>
        <option value="*">*</option>
        <option value="/">/</option>
        <option value="%">%</option>
      </select>--请选择操作符
      <input type="text" name="num2" >
      <input type="submit" name="reg" value="计算" >
    </form>
    <br />
    <hr />
    <?php
      error_reporting(E_ALL&~E_NOTICE);
      $num1=$_POST['num1'];
      $num2=$_POST['num2'];
      $num3=0;
      $pt=$_POST['pt'];
      $reg=$_POST['reg'];
      if($reg=='计算'){
        if(is_numeric($num1) && is_numeric($num2)){
          switch ($pt) {
            case '+':
              $num3=$num1+$num2;
              break;
            case '-':
              $num3=$num1-$num2;
              break;
            case '*':
              $num3=$num1*$num2;
              break;
            case '/':
              if($num2==0){
                die('0不能为除数！');
              }
              $num3=$num1/$num2;
              break;
            case '%':
              $num3=$num1%$num2;
              break;
            default:
              exit('请选择合法操作符');
          }
          echo "计算结果:{$num1}{$pt}{$num2}={$num3}";
        }else{
          exit('请输入合法整数！');
        }
      }
    ?>
  </body>
</html>

Mr_zhang 2017-07-18

源自：流程控制 1-15 简易计算器的实现