通过TreeSet调用iterator.next（）[Thinking in Java] [英] Calling iterator.next() through a TreeSet [example from Thinking In Java]

问题描述

Java中的Thinking in Depth中的读取容器。看到这个例子（从SortedMapDemo.java修改）：

 TreeSet< String> sortedSet =  new  TreeSet< String>（）; 
 Collections.addAll（sortedSet，
   abcdefgh 
。 split（ ））; 
 

...

 Iterator< String> it = sortedSet.iterator（）; 
  for （ int  i =  0 ; i< =  6 ; i ++）{
  if （i == < span class =code-digit> 3 ）low = it.next（）; 
  if （i ==  6 ）high = it.next（）; 
  else  it.next（）; 
} 
打印（低）; 
打印（高）; 

令我感到困惑的是，虽然'low'打印出d，high打印出h，我认为应该是g。

如果我们在每次迭代中调用it.next（），第7次迭代不应该给出g??

解决方案

解决。对不起伙计。

这是因为



if;

if;

否则;



结构，当i == 3时，.next（）被调用两次

Reading Containers in Depth chapter from the Thinking In Java book. Saw this example(modified from SortedMapDemo.java):

TreeSet<String> sortedSet = new TreeSet<String>();
Collections.addAll(sortedSet,
          "a b c d e f g h"
            .split(" "));

...

Iterator<String> it = sortedSet.iterator();
for(int i = 0; i <= 6; i++) {
if(i == 3) low = it.next();
if(i == 6) high = it.next();
else it.next();
}
print(low);
print(high);

What baffles me is that while 'low' prints out "d", 'high' prints out "h", for which I think should be "g" instead.
If we're calling it.next() in each iteration, shouldn't the 7th iteration gives "g"??

解决方案

Solved. Sorry guys.
It's because the

if;
if ;
else;

structure, when i ==3, .next() gets called twice

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