// Examples of working with the Standard Template Library (the STL)
//
// Here is a comparison of C++ structures and corresponding Java structures:
//     C++ structure     Java structure
//     --------------------------------
//     vector            ArrayList
//     list              LinkedList
//     set               TreeSet
//     multiset          no equivalent
//     map               TreeMap
//     pair              Map.Entry
//
// Basic operations on the structure:
//     function/operator      vector    list     set    multiset
//     ---------------------------------------------------------
//     push_back(value)         x        x        -        -
//     push_front(value)        -        x        -        -
//     insert(value)            -        -        x        x
//     back()                   x        x        -        -
//     front()                  x        x        -        -
//     pop_back()               x        x        -        -
//     pop_front()              -        x        -        -
//     x[index]                 x        -        -        -
//     size()                   x        x        x        x
//     empty()                  x        x        x        x
//     clear()                  x        x        x        x
//      ==, !=, <, >, <=, >=    x        x        x        x
// 
// Use of iterators on the structure:
//     function/operator      vector    list     set    multiset
//     ---------------------------------------------------------
//     begin()                  x        x        x        x
//     end()                    x        x        x        x
//     iterator++               x        x        x        x
//     iterator--               x        x        x        x
//     *iterator (const)        x        x        x        x
//     *iterator (reference)    x        x        -        -
//     iterator+n and +=n       x        -        -        -
//     iterator-n and -=n       x        -        -        -
//     erase(iterator)          x        x        x        x
//     insert(iterator, value)  x        x        x        x

#include <iostream>
#include <string>
#include <vector>
#include <set>
#include <sstream>

using namespace std;

// returns a string version of the given vector as a comma-separated,
// bracketed, list
string vector_to_string(const vector<int> & v) {
    ostringstream out;
    out << "[";
    if (v.size() > 0) {
        out << v[0];
        for (int i = 1; i < v.size(); i++) {
            out << ", " << v[i];
        }
    }
    out << "]";
    return out.str();
}

int main() {
    vector<int> v {9, -8, 13, 9, 6, 12, 42, 17, -8, 200};
    cout << vector_to_string(v) << endl;
    auto itr = v.begin();
    *(itr + 5) = 35;
    cout << *itr << endl;
    itr = v.end();
    cout << *itr << endl;
    cout << vector_to_string(v) << endl;
    cout << endl;
    
    // print the size of the vector
    cout << "size = " << v.size() << endl;
    cout << "size also = " << v.end() - v.begin() << endl;
    // print out the midpoint
    cout << *(v.begin() + (v.end() - v.begin()) / 2) << endl;
    cout << endl;

    // inserts a -1 in front of every even #
    cout << "v = " << vector_to_string(v) << endl;
    for (auto itr = v.begin(); itr < v.end(); itr++) {
        if (*itr % 2 == 0) {
            itr = v.insert(itr, -1);
            itr++;
        }
    }
    cout << "v = " << vector_to_string(v) << endl;
    cout << endl;

    // prints the values in reverse order
    for (auto itr = v.end() - 1; itr >= v.begin(); itr--) {
        cout << *itr << " ";
    }
    cout << endl;
    // this works for vectors, but for non-vector types, you would instead say:
    // auto itr = s1.end();
    // while (itr != s1.begin()) {
    //     itr--;
    //     cout << *itr << endl;
    // }
    // cout << endl;
    

    // add some multiple of 3 and then loop to remove all multiples of 3
    v.push_back(30);
    v.push_back(18);
    v.push_back(3);
    v.push_back(17);
    cout << "v = " << vector_to_string(v) << endl;
    /*
    for (auto itr = v.begin(); itr < v.end(); itr++) {
        if (*itr % 3 == 0) {
            itr = v.erase(itr);
            itr--;
        }
    }
    */
    // the while loop solution is safer because it doesn't rely on
    // setting an iterator to a position out of range when vector
    // starts or ends with a multiple of 3 
    itr = v.begin();
    while (itr < v.end()) {
        if (*itr % 3 == 0) {
            itr = v.erase(itr);
        } else {
            itr++;
        }
    }
    cout << "v = " << vector_to_string(v) << endl;

    return 0;
}