std::string

 /*************************************************************************
     > File Name: string.cpp
     > Author: lukey
     > Mail: lukey123@foxmail.com
     > Created Time: Wed 10 Jun 2015 09:21:32 PM CST
  ************************************************************************/

 #include<iostream>
 //using namespace std;

 int main(int argc, char* argv[])
 {
     std::string str1 = "hello";
     std::string str2("world");
     std::cout << "str1:" << str1 << std::endl;
     std::cout << "str2:" << str2 << std::endl;
     std::string str3 = str1 + str2;
     std::cout << "str3:" << str3 << std::endl;
     std::string sub1 = str3.substr(,);
     std::string sub2 = str3.substr(,);
     std::string sub3 = str3.substr(,);
     std::string sub4 = str3.substr(,);
     std::cout << "sub1:" << sub1 << std::endl;
     std::cout << "sub2:" << sub2 << std::endl;
     std::cout << "sub3:" << sub3 << std::endl;
     std::cout << "sub4:" << sub4 << std::endl;

     return ;
 }