1.7 计算器
<body>
<?php
$num1=''; //$num1的初始值
$num2=''; //$num2的初始值
$op=''; //操作符
$result=''; //结果
if(!empty($_POST)) {
$num1=$_POST['num1'];
$num2=$_POST['num2'];
$op=$_POST['op']; //操作符
switch($op){
case '+':
$result=$num1+$num2;
break;
case '-':
$result=$num1-$num2;
break;
case '*':
$result=$num1*$num2;
break;
case '/':
$result=$num1/$num2;
break;
}
}
?>
<form method="post" action="">
<input type="text" name="num1" value='<?php echo $num1?>'>
<select name="op">
<option value="+" <?php echo $op=='+'?'selected':''?>>+</option>
<option value="-" <?php echo $op=='-'?'selected':''?>>-</option>
<option value="*" <?php echo $op=='*'?'selected':''?>>*</option>
<option value="/" <?php echo $op=='/'?'selected':''?>>/</option>
</select>
<input type="text" name="num2" value='<?php echo $num2?>'>
<input type="submit" name="button" value="=">
<input type="text" name="result" value='<?php echo $result?>'>
</form>
</body>运行结果
