数组4

#include<string>
#include<iostream>
using namespace std;
inline void test(const char *title,bool value){
cout<<title<<"returns"<<(value?"true":"false")<<endl;
}
int main()
{
string s1="DEF";
cout<<"s1 is"<<s1<<endl;
string s2;
cout<<"Please enter s2:";
cin>>s2;
cout<<"length of s2:"<<s2.length()<<endl;
test("s1<=\"ABC\"",s1<="ABC");
test("\"DEF\"<=s1","DEF"<=s1);
s2+=s1;
cout<<"s2=s2+s1:"<<s2<<endl;
cout<<"length of s2:"<<s2..length()<<endl;
return 0;
}