added a function to alter teh difficulty as the snake's getting bigger and bigger

include/Graphics.h

@@ -22,3 +22,5 @@ void printChar(int y, int x, graphics_input img);
 void printMsg(int y, int x, char *str);
 char readChar(int y, int x);
 int readInpt();
+
+void advanceDifficulty(void);

src/Controller.cpp

@@ -23,6 +23,7 @@ int Controller::act(void){
 
     if (snake->hasBitSnack(this->snack.getY(), this->snack.getX()) == true)
     {
+        advanceDifficulty();
         generateSnack(this->snack);
         this->snake->incSize();
     }

src/Graphics.cpp

@@ -75,3 +75,7 @@ int readInpt(){
     return getch();
 }
 
+void advanceDifficulty(void){
+    if(sleepTime > 28000000) // we set 28000000 as teh min sleep time
+        sleepTime -= 1000000;
+}

src/Snack.cpp

@@ -10,8 +10,8 @@ void generateSnack(Point &snack){
 
     int x, y;
     
-    x = (rand() + 1) % GAME_RIGHT_WALL_X;
-    y = (rand() + 1) % GAME_BOTTOM_WALL_Y;
+    x = rand() % GAME_RIGHT_WALL_X + 1;
+    y = rand() % GAME_BOTTOM_WALL_Y + 1;
     
     snack.setPoint(y, x);