spring_emulation.cpp

#include <iostream>
#include <cmath>
#include <windows.h>
#define         GRAVITY         9.81
#define         EPSILON         1e-5
#define         FRICTION        0.3

void draw(double position)

{
        int screen_pos = static_cast<int>(std::round(position));

        for (int i = -20; i < screen_pos; ++i)
                std::cout << "-";

        std::cout << " []\n";
}

int main()

{
        double mass_;
        std::cout << "Enter Mass (kg): ";
        std::cin >> mass_;

        double spring_constant_;
        std::cout << "Enter Spring Constant (N/m): ";
        std::cin >> spring_constant_;

        double displacement_;
        std::cout << "Enter Initial Displacement (m): ";
        std::cin >> displacement_;

        double position_      = displacement_;
        double velocity_      = 0.0;
        double acceleration_  = 0.0;

        double time_  = 0.0;
        double dt_    = 0.05;


        while (time_ <= 20.0)
        
        {
                double spring_acc   =  -spring_constant_ * position_ / mass_;

                int sign_vel        =  (velocity_ > 0) - (velocity_ < 0);
                
                double friction_acc =  -FRICTION * GRAVITY * sign_vel;

                double total_acc    =  spring_acc + friction_acc;

                if (std::abs(velocity_) < EPSILON && std::abs(total_acc) < FRICTION * 9.81)
                
                {
                        velocity_     =  0.0;
                        
                        acceleration_ =  0.0;
                        
                        draw(position_);
                
                        break;
                }

                acceleration_  =   total_acc;
                
                velocity_      +=  acceleration_ * dt_;
         
                position_      +=  velocity_ * dt_;

                draw(position_);

                Sleep(75); 
         
                time_  +=  dt_;
        }
        
        std::cout << "Simulation stopped. Final position: " << position_ << "\n";
        
        return 0;
}