std::string 各种操作

最新推荐文章于 2024-10-15 16:15:02 发布

原创最新推荐文章于 2024-10-15 16:15:02 发布 · 658 阅读

CC 4.0 BY-SA版权

本文通过一个具体的C++程序示例介绍了如何使用标准库中的字符串类进行操作，包括查找特定子串的位置、提取子串以及替换字符串内容等实用功能。

#include <string>

std::string str_strtest="username=123@qq.com&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';