<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>计算器</title>
</head>
<body>
<?php
@$a = $_GET['a']; //get接收a
@$b = $_GET['b']; //get接收b
@$operation = $_GET['operation']; //get接收运算符号
$sum = 0; //结果初始化为0
switch ($operation){ //switch选择运算方法
case '+':
$sum = $a+$b;
break;
case '-':
$sum = $a-$b;
break;
case'*':
$sum = $a*$b;
break;
case '/':
if ($b==0){
echo "除数不能为0";
break;
}
$sum = $a/$b;
break;
}
?>
<form action="reckon.php" method="get">
<input type="number" name="a" value="<?php echo $a?>">
<select name="operation">
<option value="+" <?php if ($operation=='+'){echo 'selected="selected"';}?>>+</option>
<option value="-" <?php if ($operation=='-'){echo 'selected="selected"';}?>>-</option>
<option value="*" <?php if ($operation=='*'){echo 'selected="selected"';}?>>*</option>
<option value="/" <?php if ($operation=='/'){echo 'selected="selected"';}?>>/</option>
</select>
<input type="number" name="b" value="<?php echo $b?>">
<input type="submit" value="=">
<input type="number" name="sum" value="<?php echo $sum?>">
</form>
</body>
</html>
运行截图
