#include <stdio.h>

/* screen size - adapt to console size */
#define NUM_COLUMNS 80
#define NUM_ROWS 25

/* screen buffer */
char screen[NUM_COLUMNS][NUM_ROWS];

/* initialize buffer by setting all pixels to spaces */
void initialize_buffer() {
    for (int i = 0; i < NUM_ROWS; i++)
        for (int j = 0; j < NUM_COLUMNS; j++)
            screen[j][i] = ' ';
}


/* update screen by copying buffer to console window */
void update_screen() {
    for (int i = 0; i < NUM_ROWS; i++) {
        for (int j = 0; j < NUM_COLUMNS; j++)
            putchar(screen[j][i]);
        putchar('\n');
    }
    fflush(stdout);
}

/* checks whether a given point (x,y) is within the screen */
unsigned in_screen(int x, int y) {
    // TODO
    return 0;
}

/* draw a single point at given position (x,y) and with given character */
void draw_pixel(int x, int y, char c) {
    // TODO
}

/* clear a single pixel at position (x,y) */
void clear_pixel(int x, int y) {
    // TODO
}

/* draw a horizontal line (x1,y)-(x2,y) with dashes (-) */
void draw_horizontal_line(int x1, int x2, int y) {
    // TODO
}

/* draw a vertical line (x,y1)-(x,y2) with vertical bars (|) */
void draw_vertical_line(int x, int y1, int y2) {
    // TODO
}

/* draw a horizontal arrow (x1,y)-(x2,y) */
void draw_horizontal_arrow(int x1, int x2, int y) {
    draw_horizontal_line(x1, x2, y);
    if (x1 < x2)
        draw_pixel(x2, y, '>');
    else
        draw_pixel(x2, y, '<');
}

/* draw a vertical arrow (x,y1)-(x,y2) */
void draw_vertical_arrow(int x, int y1, int y2) {
    draw_vertical_line(x, y1, y2);
    if (y1 < y2)
        draw_pixel(x, y2, 'v');
    else
        draw_pixel(x, y2, '^');
}

/* draw a rectangle (x1,y1)-(x2,y1)-(x2,y2)-(x1,y2) with plus, dashes and vertical bars */
void draw_rectangle(int x1, int y1, int x2, int y2) {
    // TODO
}

void draw_filled_rectangle(int x1, int y1, int x2, int y2, char c) {
    // TODO
}

/* draw a general line (x1,y1)-(x2,y2) with character c */
void draw_line(int x1, int y1, int x2, int y2, char c) {
    // TODO
}

/* flood fill an area starting at given position with character c */
void flood_fill(int x, int y, char c) {
    // TODO
}


/* main program: entry point */

int main(int argc, const char *argv[]) {

    initialize_buffer();

    draw_rectangle(25, 2, 68, 8);
    draw_line(0, NUM_ROWS - 1, NUM_COLUMNS - 1, 0, '*');
    flood_fill(2, 2, '.');
    draw_pixel(30, 10, '1');
    draw_pixel(20, 15, '2');
    draw_pixel(75, 20, '3');
    draw_line(8, 8, 45, 15, '+');
    draw_horizontal_arrow(0, NUM_COLUMNS - 1, 0);
    draw_horizontal_arrow(NUM_COLUMNS - 1, NUM_COLUMNS / 2, NUM_ROWS - 2);
    draw_vertical_arrow(0, 1, NUM_ROWS - 1);
    draw_filled_rectangle(3, 3, 8, 5, '#');

    update_screen();
    return 0;
}