Shows a class that is a wrapper over a vector of objects. Includes using STL copy, and find_if, along with C++11 for each loop. See video at https://youtu.be/usBts0ccGsw.

main.cpp

#include "Student.h"
#include "Roster.h"
#include <iostream>

using namespace std;

int main() {
    Student s1 {"Cecelia", 3.8 };
    Student s2 {"Sam", 3.1};

//    cout << s1 << endl;
//    cout << s2 << endl;
    Roster roster;
    roster.add(s1);
    roster.add(s2);

    cout << roster << endl;
    cout << roster.find("Cecelia") << endl;
    cout << roster.find("Sam") << endl;
    cout << roster.find("Max") << endl;

}

Roster.cpp

#include <iterator>
#include <algorithm>
#include "Roster.h"

Roster::Roster() { }

void Roster::add(Student& student) {
    students.push_back(student);
}

Student Roster::find(string name) const {
//    for (int i = 0; i < students.size(); i++) {
//        if (students.at(i).get_name() == name) {
//            return students.at(i);
//        }
//    } // end for loop
//    for (auto student : students) {
//        if (student.get_name() == name) {
//            return student;
//        }
//    } // end for loop

    auto name_match_fn = [name](auto student) {
        return student.get_name() == name;
    };

    auto student_it = find_if(begin(students), end(students), name_match_fn);
    if (student_it == end(students)) {
        // no match found
        return Student();
    }
    else {
        return *student_it;
    }
}

/**
 * Overloaded output operator for Roster.
 * @param ostr the output stream to write to.
 * @param roster the Roster to output.
 * @return the (modified) ostream.
 */
ostream& operator<<(ostream& ostr, const Roster& roster) {
    ostr << "{ ";

    // copy up to but not including the last element
    // putting a "; " after each one
    copy(begin(roster.students), end(roster.students) - 1,
         ostream_iterator<Student>(ostr, "; "));

    // now output the last element (without a trailing "; ")
    if (roster.students.size() > 0) {
        ostr << roster.students.at(roster.students.size() - 1) << ' ';
    }

    ostr << "}";
    return ostr;
}

Roster.h

#ifndef STUDENTDB_ROSTER_H
#define STUDENTDB_ROSTER_H

#include "Student.h"
#include <vector>
#include <iostream>

using namespace std;

class Roster {
    vector<Student> students;
public:
    Roster();

    void add(Student& student);

    Student find(string name) const;

    friend ostream& operator<<(ostream& ostr, const Roster& roster);
};

ostream& operator<<(ostream& ostr, const Roster& roster);

#endif //STUDENTDB_ROSTER_H

Student.cpp

#include "Student.h"

using namespace std;

Student::Student(string theName, double theGpa) : name(theName), gpa(-1) {
    set_gpa(theGpa);
}

// accessor
string Student::get_name() const {
    return name;
}

// mutator
void Student::set_gpa(double newGpa) {
    if (newGpa >= 0 && newGpa <= 4.0) {
        gpa = newGpa;
    }
}

ostream& operator<<(ostream& ostr, const Student& stud) {
    ostr << stud.get_name() << ", " << stud.gpa;
    return ostr;
}

Student.h

#ifndef STUDENTDB_STUDENT_H
#define STUDENTDB_STUDENT_H

#include <string>
#include <iostream>

using namespace std;

class Student {
//private:
    string name;
    double gpa;

public:
    Student() : name(""), gpa(-1) { }

    Student(string theName, double theGpa);

    // accessor
    string get_name() const;

    // mutator
    void set_gpa(double newGpa);

    friend ostream& operator<<(ostream& ostr, const Student& stud);
};

ostream& operator<<(ostream& ostr, const Student& stud);

#endif //STUDENTDB_STUDENT_H