for_each + lambda 优雅的写代码

写惯了objective c 的 block代码，实现在方便，省事，代码简洁，c++的lambda也可以写得很简洁，记录下

lambda传递局部参数，请将参数写在[]中。

boost::property_tree::ptree pt;
    try {
        boost::property_tree::ini_parser::read_ini(path, pt);  // 打开读文件  
        accountitem itm;
        i = 1;
        for_each(acs.begin(), acs.end(), [&pt,&i,&itm](accountitem x) {
            string s1, s2;
            s1 = str::format("帐号%d.账号%d", i, i);
            pt.put<std::string>(s1, x.name);
            s1 = str::format("帐号%d.密码%d", i, i);
            pt.put<std::string>(s1, x.password);
            i++;
        });
        boost::property_tree::ini_parser::write_ini(path, pt);
    }
    catch (std::exception e) {
        cout << e.what();
        boost::property_tree::ini_parser::write_ini(path, pt);
    }