c＋＋，比较两字符串的大小，对应位置相减，输出结果，用数组和指针分别做，

数组：

#include <iostream>
using namespace std;

void main()
{
char a[20],b[20];
cout<<"Please input a and b"<<endl;
cin>>a>>b;
for(int i = 0;i<20;i++)
{
if(a[i] > b[i])
{
cout<<"String a is the big one"<<endl<<"difference: "<<a[i]-b[i]<<endl;
break;
}
else
if(a[i] < b[i])
{
cout<<"String b is the big one"<<endl<<"difference: "<<b[i]-a[i]<<endl;
break;
}
else
continue;
}
if(i == 20)
{
cout<<"Equal"<<endl;
}
}