使用反向Iterator将句子反转输出

反向迭代器reverse_Iterator的表示范围，以及反向迭代器和正向Iterator的转化关系见下图:
反向Iterator执行自增操作是向前移动，自减是向后移动

下面是一个使用Reverse_Iterator将一个句子进行反向输出的例子

    std::string line = "Nothing is impossible";
    std::string::reverse_iterator findIt;
    std::string::reverse_iterator tempIt = line.rbegin();
    findIt = find(line.rbegin(),line.rend(),' ');
    //The operator== used to determine the match between an element and the specified value must impose an equivalence relation between its operands.
    //In practice,if you want to use it with an object or a struct,you must overload the operator ==
    while(findIt != line.rend())
    {
        cout<.base(),tempIt.base());//[)
        //function base which convert reverse_iterator to iterator
        cout<<" ";
        tempIt = findIt + 1;
        findIt = find(findIt+1,line.rend(),' ');//[)
    }
    //We need to do special process to the first word
    cout<     cout<