#include <string>

 1 #include <iostream>
 2 #include <string>
 3 using namespace std;
 4 int main()
 5 {
 6     string s("0123456789");
 7     cout<<s<<endl;
 8     cout<<s[1]<<endl;//也是从０位开始
 9     return 0;
10 }

 1 #include <iostream>
 2 #include <string>
 3 using namespace std;
 4 int main()
 5 {//得出 重载符 比较的是字典序 不是长度
 6     string ss[2];
 7     while(cin>>ss[0]>>ss[1])
 8     {
 9         cout<<ss[0]<<" "<<ss[1]<<endl;
10         cout<<" < : "<<(ss[0]<ss[1])<<endl;
11         cout<<" > : "<<(ss[0]>ss[1])<<endl;
12         cout<<" <= : "<<(ss[0]<=ss[1])<<endl;
13         cout<<" >= : "<<(ss[0]>=ss[1])<<endl;
14         cout<<" == : "<<(ss[0]==ss[1])<<endl;
15     }
16     return 0;
17 }