<html>
<head>
<title>PHP实现简单计算器</title>
<meta http-equiv="Content-Type" content="text/html;charset=utf-8">
</head>
<?php
$num1=true;
$num2=true;
$numa=true;
$numb=true;
$message="";
//单路分支
if(isset($_GET["sub"])){
if($_GET["num1"]==""){
$num1=false;
$message.="第一个数不能为空";
}
if(!is_numeric($_GET["num1"])){
$numa=false;
$message.="第一个数不是数字";
}
if($_GET["num2"]==""){
$num2=false;
$message.="第二个数不能为空";
}
if(!is_numeric($_GET["num2"])){
$numb=false;
$message.="第二个数不是数字";
}
if($num1 && $num2 && $numa && $numb) {
$sum=0;
//多路分支switch
switch($_GET["ysf"]){
case "+":
$sum=$_GET["num1"]+$_GET["num2"];
break;
case "-":
$sum=$_GET["num1"]-$_GET["num2"];
break;
case "x":
$sum=$_GET["num1"]*$_GET["num2"];
break;
case "/":
$sum=$_GET["num1"]/$_GET["num2"];
break;
case "%":
$sum=$_GET["num1"]%$_GET["num2"];
break;
}
}
}
?>
<body>
<table align="center" border="1" width="500">
<caption><h1>计算器</h1></caption>
<form action="lx.php">
<tr>
<td>
<input type="text" size="5" name="num1" value="<?php
if(isset($_GET["num1"])){
echo $_GET["num1"];}
else {echo '';} ?>" >
</td>
<td>
<select name="ysf">
<option value="+">+</option>
<option value="-">-</option>
<option value="x">x</option>
<option value="/">/</option>
<option value="%">%</option>
</select>
</td>
<td>
<input type="text" size="5" name="num2" value="<?php
if(isset($_GET["num2"])){
echo $_GET["num1"];}
else {echo '';} ?>">
</td>
<td>
<input type="submit" name="sub" value="计算">
</td>
</tr>
<?php
if(isset($_GET["sub"])){
echo '<tr><td colspan="5">';
if($num1 && $num2 && $numa && $numb){
echo "结果："." = ".$sum;
}else{
echo $message;
}
echo '</td></tr>';
}
?>
</form>
</table>
</body>
</html>