public boolean setMode()
	{
		//keeps track of valid input
		boolean successfulSetMode = false;
		//a loop prompts the user with the same question if the input is not valid
		do
		{
			System.out.println("Please choose: s = standard mode ( 4 pegs/6 colors)");
			System.out.println("               c = challenge mode( 5 pegs/7 colors)");
			input = keyboard.nextLine();
			
			if (input.equalsIgnoreCase("s"))
			{
				mode = STANDARD_MODE;
				successfulSetMode = true;
				return true;
			}
			else if (input.equalsIgnoreCase("c"))
			{
				mode = CHALLENGE_MODE;
				successfulSetMode = true;
				return true;
			}
			else
			{
				System.out.println("Error in reading your input.");
				successfulSetMode = false;
			}
		}
		//keep looping if the input is not valid
		while (!successfulSetMode);
		
		return successfulSetMode;
	}//setMode()