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;
}