Effective Java第29条--将局部变量的作用域最小化

<span style="font-family: Arial, Helvetica, sans-serif; background-color: rgb(255, 255, 255);">一，有两个迭代器的遍历：</span>

<span style="font-size:18px;">Iterate i = c1.iterator();
while(i1.hasNext()){</span>

<span style="font-size:18px;"><span style="white-space:pre">	</span>doSomething(i.next());
}</span>

<pre name="code" class="java"><span style="font-size:18px;">i = c2.iterator();
while(i.hasNext()){//由于复制粘贴导致忘记改变量名称</span>

<span style="font-size:18px;"><span>	</span>doSomething(i.next());
}</span>

<span style="font-size: 24px;"><strong>在编译时不会报错，但是运行时，将会导致第二个迭代器不会遍历到。</strong></span>

<span style="font-size:24px;"><strong>优雅的修改如下：</strong></span>

<strong><span style="font-size:18px;">
</span></strong>

<span style="font-size:18px;">for(Iterator i = c.iterator();i.hasNext();){
doSomething(i.next());
}</span>

<span style="font-size:18px;">for(int i=0;i<list.size();i++){
doSomething(list.get(i));
}</span><span style="font-size:24px;">
</span>

<span style="font-size:18px;">for(int i=0,n=list.size();i<n;i++){
doSomething(list.get(i));
}</span>