日期:2014-05-17  浏览次数:20328 次

PHP简单计算器

这个是运用PHP的条件控制语句写的,比较简单,消化下...

<html>
	<head>
		<title>PHP实现简单计算器(使用分支结构)</title>
	</head>
	<body>
		<?php
			$mess = "";
			if( isset( $_POST["sub"])){
				if( $_POST["num1"] == ""){
					$mess .= "第一个数不能为空!<br>";
				}
				else if( !is_numeric($_POST["num1"])){
					$mess .= "第一个数必须为数字!<br>";
				}
			
				if( $_POST["num2"] == ""){
					$mess .= "第二个数不能为空!<br>";
				}
				else{
					if( !is_numeric($_POST["num2"])){
						$mess .= "第二个数必须为数字!<br>";
					}
					else if( $_POST["opt"] == "/" && $_POST["num2"] == 0){
						$mess .= "除数不能为0";
					}
				}
			}
		?>
	<table border="1" align="center" width="400">
		<form action="" method="post">
			<caption><h1>计算器</h1></caption>
			<tr>
				<td>
					<input type="text" size="4" name="num1" value="<?php echo $_POST["num1"] ?>" />
				</td>
				
				<td>
					<select name="opt">
						<option value="+"<?php echo $_POST["opt"] == "+" ? "selected" : "" ?>>+</option>
						<option value="-"<?php echo $_POST["opt"] == "-" ? "selected" : "" ?>>-</option>
						<option value="x"<?php echo $_POST["opt"] == "x" ? "selected" : "" ?>>x</option>
						<option value="/"<?php echo $_POST["opt"] == "-" ? "selected" : "" ?>>/</option>
						<option value="%"<?php echo $_POST["opt"] == "%" ? "selected" : "" ?>>%</option>
					</select>
				</td>
				
				<td>
					<input type="text" size="4" name="num2" value="<?php echo $_POST["num2"] ?>" />
				</td>
				
				<td>
					<input type="submit" name="sub" value="计算" />
				</td>
			</tr>
		</form>
		<?php
			if(isset($_POST["sub"])){
				echo '<tr><td colspan="4">';
				if( !$mess){
					$sum = 0;
					switch($_POST["opt"]){
						case "+":
							$sum = $_POST["num1"] + $_POST["num2"];break;
						case "-":
							$sum = $_POST["num1"] - $_POST["num2"];break;
						case "x":
							$sum = $_POST["num1"] * $_POST["num2"];break;
						case "/":
							$sum = $_POST["num1"] / $_POST["num2"];break;
						case "%":
							$sum = $_POST["num1"] % $_POST["num2"];break;
					}
					
					echo "结果: {$_POST['num1']} {$_POST['opt']} {$_POST['num2']} = {$sum}"; 
				}
				else{
					echo $mess;
				}
				
				echo '</td></tr>';
			}
		?>
		</table>
	</body>	
</html>