Tower of Hanoi game with the ability to choosing the number of discs.

TowerOfHanoi.cpp

// written by LaVanTien . You have all rights to use and modify this source code :)
// compiled with flag: -std=c++14
#include <iostream>
#include <vector>
#include <cmath>
using namespace std;
 
static vector<int> a, b, c; // 3 towers, start at 'a' and end at 'c'
static int num; // number of discs
static int sum = 0; // number of steps
 
static void newGame() {
    a.clear();
    b.clear();
    c.clear();
    if (num <= 0 || num > 15) { // maximum 15 discs, to protect user's computer :v
        num = 2;
    }
    for (int i = num; i > 0; --i) {
        a.push_back(i);
    }
}
 
static void print() { // print step
    int na = a.size();
    int nb = b.size();
    int nc = c.size();
    cout << "\n--";
    for (int i = 0; i < num; ++i) {
        cout << "--";
    }
    cout << "\nA: ";
    if (na != 0) {
        cout << a[0];
    }
    for (int i = 1; i < na; ++i) {
        cout << ',' << a[i];
    }
    cout << '\n';
    cout << "B: ";
    if (nb != 0) {
        cout << b[0];
    }
    for (int i = 1; i < nb; ++i) {
        cout << ',' << b[i];
    }
    cout << '\n';
    cout << "C: ";
    if (nc != 0) {
        cout << c[0];
    }
    for (int i = 1; i < nc; ++i) {
        cout << ',' << c[i];
    }
    cout << '\n';
    cout << "--";
    for (int i = 0; i < num; ++i) {
        cout << "--";
    }
    cout << '\n';
}
 
static unsigned long long preCalc() {
    unsigned long long res = (unsigned long long)pow(2, num) - 1;
    return res;
}
 
static void md(vector<int> &u, vector<int> &v) { // move disc
    v.push_back(u.back());
    u.pop_back();
    ++sum;
    cout << "\nStep " << sum << ':';
    print();
}
 
static void solve(const int n, vector<int> &u, vector<int> &v, vector<int> &t) {
    if (n > 0) { // recursive calls
        solve(n - 1, u, t, v); // first move n - 1 discs from A to B
        md(u, v); // then move the last disc to C
        solve(n - 1, t, v, u); // last, move all n - 1 discs from B to C
    } // that's all the idea, pretty simple :)
}
 
static void playBot() {
    cout << "\nOriginal state:";
    print();
    solve(num, a, c, b);
}
 
int main() {
    cout << "_/\\_/\\_/\\_ \"Tower of Ha Noi\" Solver _/\\_/\\_/\\_\n";
    cout << "\nEnter number of disc: ";
    cin >> num;
    cout << "\nMinimum number of steps: " << preCalc() << '\n';
    cout << "Continue? (press any key to continue) ";
    cin.get();
    cin.get();
    newGame();
    playBot();
    cout << "\nDone in " << sum << " steps.\n";
    cin.get();
    return 0;
}