Multiple undeclared identifier on simple C++ program

I don't really have the hang of declaring identifiers. This is the code I have:

#include "pugi/pugixml.hpp"

#include <iostream>
#include <string>
#include <map>

int main() {
    pugi::xml_document doca, docb;
    std::map<std::string, pugi::xml_node> mapa, mapb;

    if (!doca.load_file("a.xml") || !docb.load_file("b.xml"))
        return 1;

    for (auto& node: doca.child("site_entries").children("entry")) {
        const char* id = node.child_value("id");
        mapa[id] = node;
    }

    for (auto& node: docb.child("site_entries").children("entry"))
        const char* idcs = node.child_value("id");
        if (!mapa.erase(id)) {
            mapb[id] = node;
        }
    }

    for (auto& ea: mapa) {
        std::cout << "Removed:" << std::endl;
        ea.second.print(std::cout);
    }

    for (auto& eb: mapb) {
        std::cout << "Added:" << std::endl;
        eb.second.print(std::cout);
    }

I get quite a few errors when trying to compile but one that comes up a few times is the error error: use of undeclared identifier for example:

• src/main.cpp:21:25: error: use of undeclared identifier 'id' if (!mapa.erase(id)) { ^


• src/main.cpp:22:18: error: use of undeclared identifier 'id' mapb[id] = node; ^


• src/main.cpp:22:24: error: use of undeclared identifier 'node' mapb[id] = node;

After reading this topic it seems to be talking about not including iostream without string, but I have done this.

http://ift.tt/1PYqzPW

I'm very new to C++ so any help would be appreciated.