请教高手一条C++问题

编写一程序，将字符串s1和s2比较，如果s1>s2，输出一个正数；s1=s2，输出0；s1<s2，输出一个负数。不用strcmp函数。两个字符串用gets函数读入.
请用数组解答!!!
用数组答阿!!

#include <iostream>
#include <cstdio>
using namespace std;

void main()
{
int i = 0;
char s1[20], s2[20];

cout << "input s1:" << endl;
gets(s1);
cout << "input s2:" << endl;
gets(s2);

do
{
if(s1[i] > s2[i])
{
cout << "1" << endl;
break;
}

if(s1[i] < s2[i])
{
cout << "-1" << endl;
break;
}
i++;
}while(s1[i] != '\0' && s2[i] != '\0');

if(s1[i] == '\0' && s2[i] == '\0')
{
cout << "0" << endl;
}
}
C++风格：
#include <iostream>
#include <cstdio>
using namespace std;
class cmp
{
public:
char s1[20];
char s2[20];
public:
void eqS1( );