progression.hpp

#pragma once
 
#include <format>
#include <iostream>


class Progression {
public:
  virtual long first_value();

  virtual long next_value() = 0;

  void print_progression(int n);

  virtual ~Progression() = default;
 
protected:
  long curr;  
  long first; 
};

class ArithProgression : public Progression {
public:
  ArithProgression(long i = 1, long f = 0);

  long next_value() override;
 
  friend std::ostream &operator<<(std::ostream &out,
                                  const ArithProgression &sdt);
 
protected:
  long inc; 
};

class GeometricProgression : public Progression {
public:
  GeometricProgression(long b = 2);

  long next_value() override;
 
protected:
  long base; 
};

class FibonacciPg : public Progression {
protected:
  long sec_v; 
  long prev;  
 
public:
  FibonacciPg(long f = 0, long s = 1);

  long first_value() override;

  long next_value() override;
};
 
ArithProgression::ArithProgression(long i, long f) {
  inc = i;
  first = f;
  curr = f;
};
 
long Progression::first_value() {
  curr = first;
  return curr;
}
 
long ArithProgression::next_value() {
  curr += inc;
  return curr;
}
 
void Progression::print_progression(int n) {
  std::cout << std::format("{}", first_value());
  for (int i = 2; i <= n; ++i) {
    std::cout << std::format(" {} ", next_value());
  };
  std::cout << std::endl;
}
 
std::ostream &operator<<(std::ostream &out, const ArithProgression &apg) {
  out << "first value: " << apg.first << " Current value: " << apg.curr
      << "increment by: " << apg.inc << "\n";
 
  return out;
};

GeometricProgression::GeometricProgression(long b) : base(b) {
  first = 1;
  curr = 1;
};
 
long GeometricProgression::next_value() {
  curr *= base;
  return curr;
}

FibonacciPg::FibonacciPg(long first_value, long second_value) {
  first = first_value;
  sec_v = second_value;
  prev = sec_v - first;
}
 
long FibonacciPg::first_value() {
  curr = first;
  prev = sec_v - first;
  return curr;
}
 
long FibonacciPg::next_value() {
  long next = curr + prev;
  prev = curr;
  curr = next;
  return curr;
}