std::string 各种操作



#include <string>    

std::string str_strtest="username=[e-mail]&password=123123";    std::cout <<"str_strtest.back():111 " << str_strtest.back() <<std::endl;    std::size_t found_name = str_strtest.find("username=");    std::size_t found_and = str_strtest.find("&");    std::size_t found_password = str_strtest.find("password=");    if(found_name!=std::string::npos)    {        std::cout <<"found_name: " << found_name <<std::endl;    }    if(found_and!=std::string::npos)    {        std::cout <<"found_and: " << found_and <<std::endl;    }    if(found_password!=std::string::npos)    {        std::cout <<"found_password: " << found_password <<std::endl;    }    std::string str_myusername, str_mypassword;    str_myusername.assign(str_strtest,found_name+9,found_and-9);    std::cout << "str_myusername: " << str_myusername << std::endl;    std::cout <<"str_strtest.back():222 " << str_strtest.back() <<std::endl;    str_mypassword.assign(str_strtest,found_and+10,str_strtest.back());    std::cout << "str_mypassword: " << str_mypassword << std::endl;//    if(iter !=std::string::npos)//    {//        std::cout << " str_strtest iter: " << iter << std::endl;//        str_strtest.replace(str_strtest.find("weifuliang"),10,"sucuihuang_hahhah");//        std::cout << "str_strtest : " << str_strtest << std::endl;//    }//    std::string str("There are two needles in this haystack with needles.");//    std::string str2("needle");//    // different member versions of find in the same order as above://    std::size_t found = str.find(str2);//    if (found != std::string::npos)//        std::cout << "first 'needle' found at: " << found << '\n';//    found = str.find("needles are small", found + 1, 6);//    if (found != std::string::npos)//        std::cout << "second 'needle' found at: " << found << '\n';//    found = str.find("haystack");//    if (found != std::string::npos)//        std::cout << "'haystack' also found at: " << found << '\n';//    found = str.find('.');//    if (found != std::string::npos)//        std::cout << "Period found at: " << found << '\n';//    // let's replace the first needle://    str.replace(str.find("needles"), str2.length(), "preposition 123123123122312231123");  //replace 用法//    std::cout << str << '\n';