form表单实现简易计算 $_POST()，两种语句实现switch/if...else 

form表单实现简易计算：
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
 <head>
  <title> 计算器 </title>
  <meta name="generator" content="editplus" />
  <meta name="author" content="" />
  <meta name="keywords" content="" />
  <meta name="description" content="" />
 </head>

 <body>
<form action="calculator.php" method="post">
    <input type="text" name="num1"/>
    <select name="jisuan">
    <option>+</option>
    <option>-</option>
    <option>*</option>
    <option>/</option>
    </select>
    <input type="text" name="num2"/>
    <input type="submit" name="num3"  value="计算"/>
</form>
 <?php

 if(isset($_POST['num3'])){//首先在开始之前要先判断是否已经传值

    $num1=$_POST['num1'];
    $num2=$_POST["num2"];
    $num3=$_POST["num3"];
    $jisuan=$_POST["jisuan"];
        switch($jisuan){  //switch语句实现
            case '+':
                $num3=$num1+$num2;
            break;

            case '-':
                $num3=$num1-$num2;
            break;

            case '*':
                $num3=$num1*$num2;
            break;

            case '/':
                if($num2==0){//进行除法运算时 首先要先判断除数，除数为0时直接echo
                    echo "被除数不能为0";
                    echo $num3=''; 
                }else{
                    $num3=$num1/$num2;
                }
                break; 
        }
        echo $num3;
 }
 ?>


 






<?php
    
    if(isset($_POST['num3'])){
    $num1=$_POST['num1'];
    $num2=$_POST['num2'];
    $num3=$_POST['num3'];
    $jisuan=$_POST['jisuan'];
    if($jisuan=='+'){
        $num3=$num1+$num2;
    }elseif($jisuan=='-'){
        $num3=$num1-$num2;
    }elseif($jisuan=='*'){
        $num3=$num1*$num2;
    }elseif($jisuan='/'){
        $num3=$num1/$num2;
        if($num2==0){
            echo "被除数不能为0";
            echo $num3='';
        }else{
            $num3=$num1/$num2;
        }
    }
    echo $num3;

 }
?>






 



 </body>
</html>










        

            posted on 
2017-08-18 16:43 
muak_muak 
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