curses-rain.cpp

#include <iostream>
#include <ncurses.h> // curses library
#include <vector>
#include <cstdlib>   // rand()
#include <ctime>     // for initializing random
#include <unistd.h>  // usleep()

// Amount of drops to create on the screen
const unsigned int DROP_AMOUNT = 50;

class Raindrop {
	public:
		int m_PosY, m_PosX, m_PrevY, m_PrevX, m_Velocity;
		Raindrop(int y, int x) {
			m_PosY = y;
			m_PosX = x;
			m_Velocity = 1;
		}
		void update(int maxY, int maxX) {
            // Set previous position
			m_PrevY = m_PosY;
			m_PrevX = m_PosX;
            // Update position
			m_PosY += m_Velocity;
            // if at the bottom of the screen
			if (m_PosY >= maxY) {
				m_PosY = 0;
				m_PosX = rand() % maxX;
			}
		}
		void draw() {
            // Draw drop
			mvprintw(m_PosY, m_PosX, "|");
			// Erase previous drawn drop
            mvprintw(m_PrevY, m_PrevX, " ");
		}
};

int main() {
	initscr();
    // Initialize RNG
	srand(time(NULL));
    // Disable cursor in the terminal
	curs_set(false);
	int maxy = 0, maxx = 0;
    // Get width and height of the terminal
	getmaxyx(stdscr, maxy, maxx);

	std::vector<Raindrop> drops;
    // Add drops to the drop list
	for (int i = 0; i < DROP_AMOUNT; i++) {
		Raindrop drop(rand() % maxy, rand() % maxx);
		drops.push_back(drop);
	}

	while (true) {
		for (int i = 0; i < drops.size(); i++) {
			drops[i].update(maxy, maxx);
			drops[i].draw();
		}
		usleep(70000);
		refresh();
	}
	
	endwin();
}