[C ++] - two ways to flip the string

Title Description

The words were inverted sentence, punctuation is not upside down. . For example, I like beijing after the function becomes:. Beijing like I

Enter a description:

Each test comprises a test input:. I like beijing embodiment the input length not exceeding 100

Output Description:

After sequentially inverted output string, separated by spaces

Example 1

Input: I like beijing.
Output: beijing like I.

Thinking 1 : substr by the first string into a word into a vector, the vector and then in reverse order output words, to complete the inverted string
codes:

#include <iostream>
#include <stdlib.h>
#include <string>
#include <vector>
using namespace std;
int main()
{
	
	while (1)
	{
		string str;
		getline(cin, str);
		vector<string> v;
		int pos = 0, start = 0;
		while(pos<str.size())
		{
			pos = str.find(' ', start);
			string ret = str.substr(start, pos - start);
			v.push_back(ret);
			start = pos + 1;
		}
		
		vector<string>::reverse_iterator it = v.rbegin();
		while (it != v.rend())
		{
			cout << *it << " ";
			it++;
		}
		cout << endl;
	}
	system("pause");
	return 0;
}

2 ideas : first complete flip an entire string, and then complete the partial reversal, that is to stop after finding space, complete flip.
Code:

#include <iostream>
#include <string>
#include <algorithm>
using namespace std;
int main()
{
	string s;
	 注意这里要使用getline，cin>>s遇到空格就接收结束了
	getline(cin, s);
	 翻转整个句子 
	reverse(s.begin(), s.end()); // 翻转单词
	auto start = s.begin();
	while (start != s.end())
	{
		auto end = start;
		while (end != s.end() && *end != ' ')
			end++;
		reverse(start, end);
		if (end != s.end())
			start = end + 1;
		else
			start = end;
	}
	cout << s << endl;
	system("pause");
	return 0;
}