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灭绝师太Correction status：qualified
Teacher's comments：计算器功能可以完善一下， 比如用户没有输入第一个数，或者除法运算第二个数为0
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<?php//1.给定一个数组$arr = [23,3,45,6,78,8,34],筛选其偶数成员组成新的数组返回，请封装函数。$arr = [23,3,45,6,78,8,34];function getArr($arr){$arr1 = array();foreach($arr as $k=>$v){if($v%2==0){$arr1[$k] = $v;}}return $arr1;}echo '<pre>';print_r(getArr($arr));
界面<!DOCTYPE html><html lang="en"><head><meta charset="UTF-8"><title>计算器</title></head><body><form action="4.php" method="post"><span><label for="first">第一个数</label><input type="text" name="first" id="first"/></span><span><select name="fh" id=""><option value="+">+</option><option value="-">-</option><option value="*">*</option><option value="/">/</option></select></span><span><label for="second">第二个数</label><input type="text" name="second" id="second"/></span><span>=</span><span><input type="text" value="<?php echo $res ?>"></span><span><input type="submit" value="计算"></span></form></body></html>php代码功能：$first = $_POST['first']?? 0;$second = $_POST['second']?? 0;$fh = $_POST['fh']?? 0;switch($fh){case '+':$res = $first + $second;break;case '-':$res = $first - $second;break;case '*':$res = $first * $second;break;case '/':$res = $first / $second;break;}include_once ("./jsq.html");
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