SampleApp.MainForm.UpdateAgentPosition C# (CSharp) Method

        private double UpdateAgentPosition( ref int currentX, ref int currentY, int action )
        {
            // default reward is equal to moving reward
            double reward = moveReward;
            // moving direction
            int dx = 0, dy = 0;

            switch ( action )
            {
                case 0:         // go to north (up)
                    dy = -1;
                    break;
                case 1:         // go to east (right)
                    dx = 1;
                    break;
                case 2:         // go to south (down)
                    dy = 1;
                    break;
                case 3:         // go to west (left)
                    dx = -1;
                    break;
            }

            int newX = currentX + dx;
            int newY = currentY + dy;

            // check new agent's coordinates
            if (
                ( map[newY, newX] != 0 ) ||
                ( newX < 0 ) || ( newX >= mapWidth ) ||
                ( newY < 0 ) || ( newY >= mapHeight )
                )
            {
                // we found a wall or got outside of the world
                reward = wallReward;
            }
            else
            {
                currentX = newX;
                currentY = newY;

                // check if we found the goal
                if ( ( currentX == agentStopX ) && ( currentY == agentStopY ) )
                    reward = goalReward;
            }

            return reward;
        }