急关于 cin 与 getline的有关问题

急求一个关于 cin 与 getline的问题
//请教下高手门如何解决输入命令有空格的问题
//这样编写解决了不少其他问题但用cin接收进来的choice不能接受空格   像输入f   f就会重复输出2次tF
//如果用了getline又要2次回车才能完成输入   怎么样能一次回车就能解决f   f这重错误

#include   <string>
#include   <iostream>

using   namespace   std;

int   main   ()  
{
while(1)   {
bool   run=true;
string   choice;

cout < < "You   choice? " < <endl;
cin> > choice;

if(choice.size()> 1)   {
cout < <endl < < "Errer:   **Please   enter   correct   option!   ** " < <endl;
run=false;
}

if(run)   {
switch   (choice[0])  
{
case   'F ':   case   'f ':
cout < < "tF " < <endl;
break;
case   'N '   :   case   'n ':
cout < < "tN " < <endl;
break;
case   'P ':   case   'p ':
cout < < "tP " < <endl;
break;
case   'R ':   case   'r ':
break;
case   'A ':   case   'a ':
cout < < "tA " < <endl;
break;
case   'D ':   case   'd ':
cout < < "tD " < <endl;
break;
case   'Q ':   case   'q ':
cout < < "tQ " < <endl;
break;
case   'C ':   case   'c ':
cout < < "tC " < <endl;
default:
cout < <endl < < "Errer:   **Please   enter   correct   option   !   ** " < <endl;
}
}
}

return   0;
}




------解决方案--------------------
getline为啥要2次回车，你是VC6且没有打sp6补丁吧。
------解决方案--------------------

#include "stdafx.h "
#include <string>

using namespace std;

int main ()
{
bool run=true;
string choice;
while(1)
{
cout < < "You choice? " < <endl;
(cin> > choice).get();

if(choice.size() <1)
{
cout < <endl < < "Errer: **Please enter correct option! ** " < <endl;
run=false;
}

if(run)
{
switch (choice[0])
{
case 'F ': case 'f ':
cout < < "tF " < <endl;
break;
case 'N ' : case 'n ':
cout < < "tN " < <endl;
break;
case 'P ': case 'p ':
cout < < "tP " < <endl;
break;
case 'R ': case 'r ':
break;
case 'A ': case 'a ':
cout < < "tA " < <endl;
break;
case 'D ': case 'd ':
cout < < "tD " < <endl;
break;
case 'Q ': case 'q ':
cout < < "tQ " < <endl;
break;
case 'C ': case 'c ':
cout < < "tC " < <endl;
default:
cout < <endl < < "Errer: **Please enter correct option ! ** " < <endl;