#include <iostream>
#include <iomanip>
#include <map>
#include <string>
#include <cstdlib>
using std::cout;
using std::endl;
using std::string;

// Alias declarations
using StudentId = unsigned;
using Name = string;
using Students = std::map<StudentId,Name>;

// function prototypes
unsigned rand100u();
Students::const_iterator getInteratorForName(Students&, const Name& name);
std::ostream& operator<<(std::ostream&, const Students&);


int main()
{
    Students students;

    // insert 4 Students into the map
    students[rand100u()] = "John Lennon";
    students.insert(std::pair<StudentId,Name>(rand100u(),"Paul McCartney"));
    using Student = std::pair<StudentId,Name>;
    Student george{rand100u(),"George Harrison"};
    students.insert(george);
    StudentId ringoId = rand100u();
    Student ringo{ringoId,"Ringo Star"};
    students.insert(std::move(ringo));

    cout << students << endl;

    // What does this mean?
    students[50];
    cout << students << endl;

    // Correct the spelling of Ringo's name
    students[ringoId] = "Ringo Starr";
    cout << students << endl;

    // Remove Student 50
    students.erase(students.find(50));
    cout << students << endl;

    // What is John's number?
    cout << "John's number is " <<
         getInteratorForName(students,"John Lennon")->first << endl << endl;

    auto it = getInteratorForName(students,"Mick Jagger");
    if (it == students.end())
        cout << "Mick Jagger ain't there" << endl << endl;

    // count
    cout << "number of elements with key " << ringoId << " = "
         << students.count(ringoId) << endl;
    cout << "number of elements with key " << ringoId+1 << " = "
         << students.count(ringoId+1) << endl;
}


unsigned rand100u()
{
    return rand() % 100 + 1;
}

std::ostream& operator<<(std::ostream& out, const Students& students)
{
    out << std::left;
    for (auto it = students.begin(); it != students.end(); ++it)
    {
        out << std::setw(5) << it->first << std::setw(10) << it->second << endl;
    }
    return out;
}

Students::const_iterator
getInteratorForName(Students& Students, const string& name)
{
    for (auto it = Students.cbegin(); it != Students.cend(); ++it)
    {
        if (it->second == name) return it;
    }
    return Students.end();
}