implement lesson04

components/Snack.h

@@ -1,4 +1,5 @@
 #pragma once
+
 #include "Point.h"
 
 static constexpr int SNACK_CHAR = '*';

components/Snake.cpp

@@ -0,0 +1,78 @@
+#include "Snake.h"
+
+#include <iostream>
+
+Snake::Snake(uint32_t headY, uint32_t headX)
+    :direction_{LEFT}
+{
+    snake_.push_back(Point{headY, headX, '>'});
+
+    for (uint32_t i = 1; i <= SNAKE_DEFAULT_SIZE; i++) {
+        snake_.push_back(Point{headY, headX + i, SNAKE_BODY_CHAR});
+    }
+}
+
+void Snake::updateHead() {
+    switch (direction_) {
+    case UP:
+        snake_.front().moveUp();
+        break;
+    case DOWN:
+        snake_.front().moveDown();
+        break;
+    case LEFT:
+        snake_.front().moveLeft();
+        break;
+    case RIGHT:
+        snake_.front().moveRight();
+        break;
+    default:
+        std::cerr << "[x] This direction does not exist" << std::endl;
+        // OOPS!
+    }
+}
+
+void Snake::printSnake() const {
+    // TODO: for each point in snake_ call point.print()
+
+    Graphics::get().refreshScreen();
+}
+
+void Snake::move() {
+    auto head = snake_.begin();
+    auto second = std::next(snake_.begin());
+
+    // update the previous to head node
+    // by copying from head and setting
+    // the image to be body instead of head
+    *second = *head;
+    second->setImg(SNAKE_BODY_CHAR);
+
+    updateHead();
+
+    printSnake();
+}
+
+void Snake::moveUp(){
+    snake_.front().setImg('v');
+    direction_ = UP;
+    move();
+}
+
+void Snake::moveDown(){
+    snake_.front().setImg('^');
+    direction_ = DOWN;
+    move();
+}
+
+void Snake::moveLeft(){
+    snake_.front().setImg('>');
+    direction_ = LEFT;
+    move();
+}
+
+void Snake::moveRight(){
+    snake_.front().setImg('<');
+    direction_ = RIGHT;
+    move();
+}

components/Snake.h

@@ -0,0 +1,27 @@
+#pragma once
+
+#include <vector>
+
+#include "Point.h"
+#include "Snack.h"
+
+static constexpr int SNAKE_BODY_CHAR = 'o';
+static constexpr uint32_t SNAKE_DEFAULT_SIZE = 4;
+
+class Snake{
+private:
+    std::vector<Point> snake_;
+    int direction_;
+
+    void updateHead();
+    void printSnake() const;
+
+public:
+    Snake(uint32_t headY = LINES/2, uint32_t headX = COLS/2);
+
+    void moveUp();
+    void moveDown();
+    void moveLeft();
+    void moveRight();
+    void move();
+};

main.cpp

@@ -4,6 +4,7 @@
 
 #include "components/Point.h"
 #include "components/Snack.h"
+#include "components/Snake.h"
 #include "input-output/Graphics.h"
 
 void mainL01() {
@@ -12,6 +13,7 @@ void mainL01() {
     Point p(10,10,'X');
     p.print();
 
+    Graphics::get().refreshScreen();
     std::this_thread::sleep_for(std::chrono::seconds(10));
 
     Graphics::get().finalize();
@@ -25,6 +27,7 @@ void mainL02() {
     Point p(10,10);
     generateSnack(&p);
 
+    Graphics::get().refreshScreen();
     std::this_thread::sleep_for(std::chrono::seconds(10));
 
     Graphics::get().finalize();
@@ -33,14 +36,16 @@ void mainL02() {
 }
 
 void mainL03() {
-    Graphics::get().init("Learners Helper 02");
+    Graphics::get().init("Learners Helper 03");
 
     Point p(10,10);
 
     for (uint32_t i = 0; i < 100; i++) {
         p.moveDown();
+        Graphics::get().refreshScreen();
         std::this_thread::sleep_for(std::chrono::milliseconds(100));
         p.moveRight();
+        Graphics::get().refreshScreen();
         std::this_thread::sleep_for(std::chrono::milliseconds(100));
     }
 
@@ -61,7 +66,26 @@ void mainL03() {
     std::cout << "Helper QUIT" << std::endl;
 }
 
+void mainL04() {
+    Graphics::get().init("Learners Helper 04");
+
+    Snake snake;
+
+    for (uint32_t i = 0; i < 100; i++) {
+        snake.moveDown();
+        Graphics::get().refreshScreen();
+        std::this_thread::sleep_for(std::chrono::milliseconds(100));
+        snake.moveRight();
+        Graphics::get().refreshScreen();
+        std::this_thread::sleep_for(std::chrono::milliseconds(100));
+    }
+
+    Graphics::get().finalize();
+
+    std::cout << "Helper QUIT" << std::endl;
+}
+
 int main() {
-    mainL03();
+    mainL04();
     return 0;
 }