20180210-简易计算机:
<!DOCTYPE html>
<head>
<meta charset="UTF-8">
<title>计算机测试</title>
<style>
.tishi{
color:red;
}
</style>
</head>
<body>
<?php
//定义结果
$sum="";
//定义计算的两个参数:用三元运算符进行判断,存在则读取,不存在为空
$num1=isset($_POST['num1']) ? $_POST['num1'] : "";
$num2=isset($_POST['num2']) ? $_POST['num2'] : "";
//判断接收到的参数是否为整数
if(is_numeric($num1) && is_numeric($num2)){
//除法计算:
if($_POST['action'] == '/'){
//除数不能为空
if($num2 ==0){
echo "<span class='tishi'>除数不能为0</span>";
}else{
$sum=$num1/$num2;
}
}
//加法计算
if($_POST['action'] == "+"){
$sum=$num1+$num2;
}
//减法计算:
if($_POST['action'] == '-'){
$sum=$num1-$num2;
}
//乘法计算:
if($_POST['action'] == 'x'){
$sum=$num1*$num2;
}
}else{
echo "<span class='tishi'>请输入有效数值</span>";
}
?>
<form method="post" action="">
计算器
计算数值一:<input type="text" name="num1" value="<?php echo $num1;?>">
<select name="action">
<option value="+">+</option>
<option value="-">-</option>
<option value="x">x</option>
<option value="/">/</option>
</select>
计算数值二:<input type="text" name="num2" value="<?php echo $num2;?>">
<input type="submit" name="submit" value="=">
结果:<input type="text" name="sum" value="<?php echo $sum;?>">
</form>
</body>
</html>