Hey guys,

I created a Student class in a header file and it works just fine. The problem is I'm trying to store the Student objects into a map in main which made the compiler generate a "in file included from ..." error. I'm having trouble fixing this problem as I do not know why the map is not accepting the object as a key. The following code is my Student class and main:

#ifndef STUDENT_H
#define STUDENT_H
#include <iostream>
#include <utility>
#include <string>
typedef std::pair<std::string, std::string> Name;

class Student {
    explicit Student(const std::string& id, const std::string& firstName, const std::string& lastName)
        : id_(id), name_(toLowerString(firstName), toLowerString(lastName)){
            if(!isValidId(id) || !isValidName(name_)){
                throw "Student::Student(const string&, const string&, const string&): invalid input.";

    Student() : id_(id_) {name_.first = name_.first; name_.second = name_.second;}
    friend std::ostream& operator<<(std::ostream& os, const Student& s);
    friend std::istream& operator>>(std::istream& is, Student& s);

    std::string id_;
    Name name_;

    static bool isValidName(const Name& name){
        std::string::size_type i;

        for(i = 0; i < name.first.size(); i++){
                return false;
        for(i = 0; i < name.second.size(); i++){
                return false;
    return true;
    static bool isValidId(const std::string& id){
        std::string::size_type i;

        if(id[0] == 'a' && id.size() == 9){
            for(i = 1; i < id.size(); i++){
                    return false;
            return true;
        return false;
    static std::string toLowerString(const std::string& s){
        std::string s1 = s;
        for(std::string::size_type i = 0; i < s1.size(); i++){
            s1[i] = tolower(s1[i]);
        return s1;


inline std::ostream& operator<<(std::ostream& os, const Student& s){
    return os << s.id_ << ' ' << s.name_.first << ' ' << s.name_.second << std::endl;
inline std::istream& operator>>(std::istream& is, Student& s){
    std::string id;
    Name name;
    if(is >> id >> name.first >> name.second && Student::isValidId(id) && Student::isValidName(name)){
        s.id_ = id;
        s.name_.first = Student::toLowerString(name.first);
        s.name_.second = Student::toLowerString(name.second);
    } else
    return is;

int main(){

    string id;
    Name name;
    int score;
    Student s(id, name.first, name.second);
    map<Student, int> m;

    cout << "Enter a valid id, first name, last name, and a score: ";
    while(cin >> s >> score){

        m[s] += score;  <-problem occurs right here
        cout << "Enter a valid id, first name, last name, and a score: ";
    /*for(map<Student, int>::iterator it = m.begin(); it != m.end(); ++it){
        cout << it->first.id_ << endl;

Any help would be appreciated. Assume that the header file and the main are in seperate files.

Recommended Answers

All 5 Replies

"In file included from ..." is not the error. It tells you where the error occurs. The actual error message comes after that.

Anyway an std::map is a sorted map and thus needs its keys to be comparable to each other. So if you want to use a given type as the key of a std::map, the type either needs to have an operator< defined or you need to supply a custom comparison function (or functor) when creating the map.

Just what I needed, thanks alot sepp2k!

Unfortunately your problem is not solved, you'll have to rewrite everything, your code is illegal for you to use. By posting your code, you have granted DaniWeb an exclusive copyright license to your code according to DaniWeb's terms of service. You may no longer use it and have no rights to you code. Please delete your code from your computer. As the Terms of Service say:

Any and all information posted on DaniWeb may not be copied or used elsewhere, in any way, shape, or form, either on the Internet or in print, without prior written permission from Dani Horowitz.

Further transmission of your source code material, such as in a personal project or in handing in an assignment, may be prosecutable as criminal copyright infringement.

commented: sigh... +0

With my moderator hat on, I say:

Ignore Rash's post, he doesn't have the slightest clue what he's talking about, almost everything he said is wrong and misguided. Of course, you are free to use your code for personal projects or assignment submissions. And you still own copyrights to your code.

Sorry for the inconvenience (or scare), Rash is just throwing a tantrum against the terms of services. Why he would inflict this on innocent posters is beyond my comprehension.

Rash, even newbie posters have rights you know. And thanks mike for watching my back.

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