C++ 使用迭代器打印出集合的每个成员
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原文地址: http://stackoverflow.com/questions/10742491/
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Using an iterator to print out every member of a set
提问by user1415670
I'm trying to use an iterator to print out every member of a set. As far as I can tell from other stackoverflow answers, I have the correct formatting. When I run this code, it correctly outputs that the size of myset is 3, but it only outputs ii once. If I uncomment the line with *iter, Visual Studio throws a runtime exception saying that that "map/set iterator is not dereferencable. Any idea why?
我正在尝试使用迭代器打印出集合的每个成员。据我从其他stackoverflow答案中可以看出，我有正确的格式。当我运行此代码时，它正确输出 myset 的大小为 3，但它只输出 ii 一次。如果我用 *iter 取消注释该行，Visual Studio 会抛出一个运行时异常，指出“map/set iterator is not dereferencable。知道为什么吗？
int main()
{
set<int> myset;
myset.insert(5);
myset.insert(6);
myset.insert(7);
set<int>::iterator iter;
cout<<myset.size()<<endl;
int ii=0;
for(iter=myset.begin(); iter!=myset.end();++iter);{
//cout<<(*iter)<<endl;
ii+=1;
cout<<ii<<endl;
}
return 0;
}
回答by Smi
You have an extra ;in this line:
你;在这一行有一个额外的：
for(iter=myset.begin(); iter!=myset.end();++iter);{
This means that the loop's body is actually empty, and the following lines are executed once only.
这意味着循环体实际上是空的，下面几行只执行一次。
So change that line to this:
因此，将该行更改为：
for(iter=myset.begin(); iter!=myset.end();++iter) {
