利用标准c++流读文件

void do(){
std::string tmppath = "aa.zip";
    std::ifstream is(tmppath.c_str(), std::ios_base::binary, _SH_DENYRW);
  
    std::streampos current_pos1 = is.tellg();//记录下当前位置 
    is.seekg(0, std::ios::end);//移动到文件尾
    std::streampos nSize = is.tellg();
    is.seekg(current_pos1);
    std::cout << nSize << std::endl;

    is.clear();
    is.seekg(0);

    std::string fileContent;
    std::copy(std::istream_iterator<unsigned char>(is), std::istream_iterator<unsigned char>(), std::back_inserter(fileContent));
    std::cout << fileContent.size() << std::endl;

    is.clear();
    is.seekg(0);

    std::string fileContent2;
    std::copy(std::istreambuf_iterator<char>(is), std::istreambuf_iterator<char>(), std::back_inserter(fileContent2));
    std::cout << fileContent2.size() << std::endl;

    is.clear();
    is.seekg(0);
    std::vector<char> vecCHAR;
    std::copy(std::istream_iterator<char>(is), std::istream_iterator<char>(), std::back_inserter(vecCHAR));
    std::cout << vecCHAR.size() << std::endl;
    return 0;

}
 

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