翻转句子中单词的顺序

题目：输入一个英文句子，翻转句子中单词的顺序，但单词内字符的顺序不变。句子中单词以空格符隔开。为简单起见，标点符号和普通字母一样处理。

例如输入“I am a student.”，则输出“student. a am I”。

用了stl里的string类，方法是利用空格分析单词，从后往前遍历。写的比较笨拙.....

//翻转句子中单词的顺序
#include<iostream>
#include<string>
using namespace std;
typedef string::size_type st;
string myReverse(string sub){
	//cout<<sub<<endl;
	string s;
	s.resize(sub.size());
	for(st i=0;i<sub.size();i++)
		s[i]=sub[sub.size()-1-i];
	return s;
}
string toReverseString(string line){
	st start=0;
	string ans;
	for(st i=0;i<line.size();){
		if(line[i]==' ') {
			if(!ans.empty())
				ans+=myReverse(line.substr(start,i-start))+" ";
			else
				ans=myReverse(line.substr(start,i-start))+" ";
			start=i+1;
			i=start;
		}
		else
			i++;
	}
	ans+=myReverse(line.substr(start,line.size()-1))+" ";
	return ans;
}
string toReverseWord(string line){
	string ans;
	//ans.resize(line.size());                 //resize是使其重新分配
	st end=line.size()-1;
	for(int i=line.size()-1;i>=0;){            //所示st则i必须大于0
		cout<<i<<" ";
		if(line[i]==' '){
			cout<<"space"<<" ";
			/*if(!ans.empty())
				ans+=line.substr(i+1,end-i)+" ";
			else
				ans=line.substr(i+1,end-i)+" ";*/
			ans+=line.substr(i+1,end-i)+" ";      //和上面注释的一样
			end=i-1;
			cout<<ans<<endl;
		}
		i--;
	}
	cout<<"right"<<endl;
	ans+=line.substr(0,end+1)+" ";
	return ans;
}
int main(void){
	string line;
	//string l;
	//string deal;
	getline(cin,line);
	cout<<toReverseString(line)<<endl;
	cout<<toReverseWord(line)<<endl;
	system("pause");
	return 0;
}