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

时间 2019-11-10

标签 form 表单实现简易计算 post 两种语句 switch if...else 栏目 HTML 繁體版

原文原文链接

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'])){//首先在开始以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>