<html>
<head>
<title>php实现简单的计算器</title>
<meta http-equiv="Content-Type"content="text/html;charset=utf-8">
</head>
<?php
$num1=true;
$num2=true;
$numa=true;
$numb=true;
$message="";
if(isset($_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)
{
$sum==0;
switch ($_GET["ysf"])
{
case "+":
$sum= $_GET["num1"]+$_GET["num2"];
bre
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"jisuanqi1.php">
<tr>
<td>
<input type="text" size="5" name="num1" value=<?php echo$_GET["num1"] ?>>
</td>
<td>
<select name="ysf">
<option value="+" <?php if($_GET["ysf"]=="+") echo "selected" ?>>+</option>
<option value="-" <?php if($_GET["ysf"]=="-") echo "selected"?>>-</option>
<option value="x" <?php if($_GET["ysf"]=="x") echo "selected"?>>x</option>
<option value="/" <?php if($_GET["ysf"]=="/") echo "selected"?>>/</option>
<option value="%" <?php if($_GET["ysf"]=="%") echo "selected"?>>%</option>
</select>
</td>
<td>
<input type="text" size="5" name="num2" value=<?php echo$_GET["num2"] ?>>
</td>
<td>
<input type="submit" name="sub" value="计算">
</td>
</tr>
<?php
if(isset($_GET["sub"])){
echo '<tr><td colspan="5">';
if($num1 && $num2 && $numa && $numb){
echo "结果: " .$_GET["num1"]. " " .$_GET["ysf"]. " " .$_GET["num2"]." = ".$sum;}
else{
echo $message;
}
echo '</td></tr>';
}
?>