private static int readAnswer(BufferedReader reader, int choice_length){
		try{

			String line;
			int result = 0;
			while((line = reader.readLine()) != null){
				String choice = line.toLowerCase().trim();
				if(choice.length() != 1){
					System.out.println("Please enter a letter.");
					continue;
				}
				char answer_char = choice.charAt(0);
				result = (int) answer_char - 97;
				if(result < 0 || result > choice_length - 1){
					System.out.println("Please enter a valid letter for one of the answer choices.");
					continue;
				}

				break;
			}

			return result;
		} catch(IOException e){
			e.printStackTrace();
			return 0;
		} 

	}