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建设一个简单交互的网站(五) 
 8. 投票系统
 
 在许多时候,我们需要收集上网者和网友们的意见。例如:新版页面与旧版页面的比较;对某一事情的看法;对体育比赛结果的预测等等。这时候,你需要一个非常有效的网上调查系统。使用PHP就可以非常方便地实现你的这一构想。
 
 8.1 投票系统(mypolls.php3):
 
 <?
 $status=0;
 if(isset($polled)&&($polled=="c-e")){
 $status=1;
 }
 #echo "$status";
 if(isset($poll)&&($status==0)){
 setcookie("polled","c-e",time()+86400,"/");#time=24h
 }
 ?>
 <html>
 <head>
 <title>新版页面调查</title>
 <meta http-equiv="Content-Type" content="text/html; charset=gb2312">
 <style type="text/css">
 <!--
 .tb { border="1" bordercolor="#009933" cellspacing="0" font-size: 9pt; color: #000000}
 .head { font-family: "宋体"; font-size: 12pt; font-weight: bold; color: #009933; text-decoration: none}
 .pt9 { font-size: 9pt}
 a.p9:link { font-size: 9pt; color: #000000; text-decoration: none}
 a.p9:visited { font-size: 9pt; color: #000000; text-decoration: none }
 a.p9:hover { font-size: 9pt; color: #FF0000; text-decoration: underline}
 a.p9:active { font-size: 9pt; color: #FF0000; text-decoration: underline }
 -->
 </style>
 </head>
 <body bgcolor="#FFFFFF">
 <div class="head">与旧版页面相比较您觉得新版页面:</div><br>
 <?
 if(!isset($submit)){
 ?>
 <form action="myPolls.php3" method="get">
 <input type="radio" name="poll_voteNr" value="1" checked >
 <span class="pt9">信息量更大</span> <br>
 <input type="radio" name="poll_voteNr" value="2" >
 <span class="pt9">网页更精美</span> <br>
 <input type="radio" name="poll_voteNr" value="3" >
 <span class="pt9">没什么改进</span> <br>
 <input type="radio" name="poll_voteNr" value="4" >
 <span class="pt9">其它</span> <br>
 <input type="submit" name="submit" value="OK">
 <input type="hidden" name="poll" value="vote">
 <A HREF="myPolls.php3?submit=OK" class="p9">查看调查结果</A>
 </form>
 <?
 /*
 如果想增加其它的选项可直接加上即可
 */
 }else{
 $descArray=array(1=>"信息量更大",
 2=>"网页更精美",
 3=>"没什么改进",
 4=>"其它"
 );
 $poll_resultBarHeight = 9; // height in pixels of percentage bar in result table
 $poll_resultBarScale = 1; // scale of result bar (in multiples of 100 pixels)
 $poll_tableHeader="<table border=1 class="tb">";
 $poll_rowHeader="<tr>";
 $poll_dataHeader="<td align=center>";
 $poll_dataFooter="</td>";
 $poll_rowFooter="</tr>";
 $poll_tableFooter="</table>";
 $coutfile="data.pol";
 $poll_sum=0;
 
 // read counter-file
 if (file_exists( $coutfile))
 {
 $fp = fopen( $coutfile, "rt");
 while ($Line = fgets($fp, 10))
 {
 // split lines into identifier/counter
 if (ereg( "([^ ]*) *([0-9]*)", $Line, $tmp))
 {
 $curArray[(int)$tmp[1]] = (int)$tmp[2];
 $poll_sum+=(int)$tmp[2];
 }
 }
 // close file
 fclose($fp);
 }else{//
 for ($i=1;$i<=count($descArray);$i++){
 $curArray[$i]=0;
 }
 }
 if(isset($poll)){
 $curArray[$poll_voteNr]++;
 $poll_sum++;
 }
 echo $poll_tableHeader;
 
 // cycle through all options编历数组
 reset($curArray);
 while (list($K, $V) = each($curArray))
 {
 $poll_optionText = $descArray[$K];
 $poll_optionCount = $V;
 echo $poll_rowHeader;
 
 if($poll_optionText != "")
 {
 echo $poll_dataHeader;
 echo $poll_optionText;
 echo $poll_dataFooter;
 
 if($poll_sum)
 $poll_percent = 100 * $poll_optionCount / $poll_sum;
 else
 $poll_percent = 0;
 echo $poll_dataHeader;
 
 if ($poll_percent > 0)
 {
 $poll_percentScale = (int)($poll_percent * $poll_resultBarScale);
 }
 
 printf(" %.2f %% (%d)", $poll_percent, $poll_optionCount);
 
 echo $poll_dataFooter;
 }
 
 echo $poll_rowFooter;
 }
 
 echo "总共投票次数:<font color=red> $poll_sum</font>";
 echo $poll_tableFooter;
 echo "<br>";
 echo "<input type="submit" name="Submit1" value="返回主页" onClick="javascript:location='http://gophp.heha.net/index.html'">";
 echo " <input type="submit" name="Submit2" value="重新投票" onClick="javascript:location='http://gophp.heha.net/mypolls.php3'">";
 if(isset($poll)){
 // write counter file
 $fp = fopen($coutfile, "wt");
 reset($curArray);
 while (list($Key, $Value) = each($curArray))
 {
 $tmp = sprintf( "%s %dn", $Key, $Value);
 fwrite($fp, $tmp);
 }
 // close file
 fclose($fp);
 }
 }
 ?>
 </body>
 </html>
 
 注释:从上面我们可以看出该投票系统的基本过程:
 1、打开文件取得数据到数组$curArray(文件不存在则初始化数组$curArray)
 2、编历数组,处理数据得到所需值
 3、计算百分比,控制统计bar图像宽度
 4、将数据保存到"data.pol"中
 
 这里有一点是需要注意:这里的data.pol文本文件需要有写权限。
 
 
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