private void validateHouses() {
		
		//go through each house
		for(int i = 0; i < houseList.size(); i++)
		{
			//set zombie positions
			if(!houseList.get(i).setZombiePositions())
			{
				errorFlag = 1;
				errorString = "Couldn't place 'zombie' in house " + i + ".";
				return;
			}
			if(!houseList.get(i).setPlayerAndExit())
			{
				errorFlag = 1;
				errorString = "No valid Player/exit path in house " + i + ".";
				return;
			}
		}

	}