📄 c22_41.htm
字号:
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<title>练习题</title>
<meta name="GENERATOR" content="Microsoft FrontPage 3.0">
<script language="javascript">
function init(){
err1=err1div.style;
cor1=cor1div.style;
hint1=hint1div.style;
error1times=0;
}
function show(obj){
obj.display='';
}
function hide(obj){
obj.display='none';
}
function judge1(){
var s1=document.form1.C1.checked;
var s2=document.form1.C2.checked;
var s3=document.form1.C3.checked;
var s=(!s1)&&s2&&s3;
if(s){
error1times=0;
hide(hint1);
hide(err1);
show(cor1);
}else{
error1times++;
if(error1times==3) show(hint1);
hide(cor1);
show(err1);
}
}
</script>
</head>
<body bgcolor="#ccefcc" onLoad="init()">
<blockquote>
<div align="center"><center><table border="6" width="396" cellspacing="0" cellpadding="6"
height="102" bordercolor="#FF9933">
<tr>
<th width="620" bgcolor="#FF9933" height="11">1</th>
</tr>
<tr>
<td ALIGN="center" width="620" bgcolor="#00FFFF" height="63"><p align="left">x=2;<br>
while (1)<br>
{<br>
printf(" doggie ");<br>
if (x=1) break;<br>
}</td>
</tr>
</table>
</center></div><div align="center"><center><table border="6" width="396" cellspacing="0"
cellpadding="6" height="46" bordercolor="#FF9933">
<tr>
<th width="620" bgcolor="#FF9933" height="1">2</th>
</tr>
<tr>
<td ALIGN="center" width="620" bgcolor="#00FFFF" height="26"><p align="left">for ( ; ; )<br>
printf(" kitty ");</td>
</tr>
</table>
</center></div><div align="center"><center><table border="6" width="396" cellspacing="0"
cellpadding="6" height="46" bordercolor="#FF9933">
<tr>
<th width="620" bgcolor="#FF9933" height="1">3</th>
</tr>
<tr>
<td ALIGN="center" width="620" bgcolor="#00FFFF" height="26"><p align="left">for (x=1,
flag=0; <br>
flag || x%2; x++, flag=!flag)<br>
printf(" bunny ");</td>
</tr>
</table>
</center></div><p>判断一下, 程序 1,2 和 3中是否存在无限循环。请选择编号。</p>
<form name="form1">
<p>1.<input type="checkbox" name="C1" value="ON"> 2.<input
type="checkbox" name="C2" value="ON"> 3.<input type="checkbox"
name="C3" value="ON"><input type="button" value="确认" name="B1" onClick="judge1()"></p>
</form>
<div id="err1div" style="display:'none'"><p><font color="#FF0000">做错了。再做一次!</font>
</p>
</div><div id="cor1div" style="display:'none'"><font color="#FF0000"><p></font><font
color="#0000FF">正确! 做得很好! </font></p>
</div><div id="hint1div" style="display:'none'"><p>1: x=1 不是条件表达式。<br>
<br>
2: 在省略条件的情况下, 认为是假的。<br>
<br>
3: 注意: 每次执行时, x%2 或者 flag=1<br>
<br>
正确答案是: 2, 3</p>
</div>
</blockquote>
<p align="center"><a href="javascript:close()">关闭</a></p>
</body>
</html>
⌨️ 快捷键说明
复制代码
Ctrl + C
搜索代码
Ctrl + F
全屏模式
F11
切换主题
Ctrl + Shift + D
显示快捷键
?
增大字号
Ctrl + =
减小字号
Ctrl + -