请问用C++怎么把一个字符串反向输出来，最好用到指针和堆栈

#include<iostream>
using namespace std;
int main()
{
char a[500],b[500],*p,*q;
gets(a);
p=a;
q=b;
while(*p!='\0')
p++;
p=p-1;
while(p!=a-1)
{
*q=*p;
p--;
q++;
}
*q='\0';
puts(b);
cout<<endl;
return 0;
}

// alg_reverse.cpp
// compile with: /EHsc
#include <vector>
#include <algorithm>
#include <iostream>

int main( ) {
using namespace std;
vector <int> v1;
vector <int>::iterator Iter1;

int i;
for ( i = 0 ; i <= 9 ; i++ )
{
v1.push_back( i );
}

cout << "The original vector v1 is:\n ( " ;
for ( Iter1 = v1.begin( ) ; Iter1 != v1.end( ) ; Iter1++ )
cout << *Iter1 << " ";
cout << ")." <<