PHP实现简单计算器-原创手记-慕课网

<html>
    <head>
    <title>PHP简单计算器</title>
    <meta http-equiv="Content-Type" content="text/html;charset=utf-8" />
    <style>
        table{
              
             border:1px solid #CC9999;
             width:600px;
              
        }
        th{
            background:#CCCCCC;
        }
        td{
            background:#CCC;
            font:Georgia, "Times New Roman", Times, serif;
             
        }
        .setno{
            color:#FF0000;
        }
        .setyes{
            color:#03F;
        }
    </style>
    </head>
    <body>
    <?php
        $num1 = true; //判断第一个数是否为空
        $num2 = true; //判断第二个数是否为空
        $iszeno = true;//判断除数是否为0
        $isnum1 = true; //判断第一个数是否为有效数
        $isnum2 = true;//判断第二个数是否为有效数
        $message = ""; //记录错误消息
        if(isset($_POST["js"])){
            if($_POST["num1"] == ""){
                $num1 = false;
                $message .= "第一个数不能为0!";
            }
            if($_POST["num2"] == ""){
                $num2 = false;
                $message .= "第二个数不能为0!";
            }else{
                if( $_POST["opt"] == "/" && $_POST["num2"] == "0"){
                     
                        $iszeno = false;
                        $message .= "除数不能为0!";
                     
                }
                if($_POST["opt"] == "%" && $_POST["num2"] == "0"){
                        $iszeno = false;
                        $message .= "除数不能为0!";
                }
            }
            if(!is_numeric($_POST["num1"])){
                $isnum1 = false;
                $message .= "第一个数不是有效数,请输入一个有效数字!";
            }
            if(!is_numeric($_POST["num2"])){
                $isnum2 = false;
                $message .= "第二个数不是有效数,请输入一个有效数字!";
            }
        }
       /* */
    ?>
    <table align="center">
        <form action="jsq.php" method="post">
            <caption><h1>计算器&nbsp;&nbsp;<SUB>----by Jackie Lee</SUB></h1></caption>
            <tr>
                <th>
                <input type="text" size="4" name="num1" value = "<?php echo $_POST["num1"]?>"/>
                </th>
                <th>
                    <select name="opt">
                         <option value="+" <?php echo $_POST["opt"] == "+"?"selected":""?>>+</option>
                         <option value="-" <?php echo $_POST["opt"] == "-"?"selected":""?>>-</option>
                          <option value="*" <?php echo $_POST["opt"] == "*"?"selected":""?>>*</option>
                         <option value="/" <?php echo $_POST["opt"] == "/"?"selected":""?>>/</option>
                         <option value="%" <?php echo $_POST["opt"] == "%"?"selected":""?>>%</option>
                      </select>
                 </th>
                <th>
                <input type="text" size="4" name="num2" value = "<?php echo $_POST["num2"]?>" />
                </th>
                <th>
                <input type="submit" name="js" value="计算" />
                 
                </th>
            </tr>
            </form>
             <?php
                    if(isset($_POST["js"])){
                            echo '<tr><td colspan="4">';
                            $result = 0.0;
                            switch($_POST["opt"]){
                                case '+':
                                    $result = $_POST["num1"] + $_POST["num2"];
                                    break;
                                case '-':
                                    $result = $_POST["num1"] - $_POST["num2"];
                                    break;
                                case '*':
                                    $result = $_POST["num1"] * $_POST["num2"];
                                    break;
                                case '/':
                                    if($_POST["num2"] != "0"){
                                    $result = $_POST["num1"] / $_POST["num2"];
                                    }
                                    break;
                                case '%':
                                    if($_POST["num2"] != "0"){
                                    $result = $_POST["num1"] % $_POST["num2"];
                                    }
                                    break;
                        }
                        if(!$message){
                            echo '<font class="setyes">'."计算结果:".$_POST["num1"]." ".$_POST["opt"]." ".$_POST["num2"]." = ".$result."</font>";
                        }else{
                            echo '错误:<font class="setno">'.$message."</font>";
                             
                        }
                            echo '</td></tr>';
                    }
         
            ?>       
    </table>
    </body>
</html>