class StringUtils {

	public static String showControlCharacters(String str) {
		int len = str.length();
		StringBuilder sb = new StringBuilder();

		for (int i = 0; i < len; i += 1) {
			char c = str.charAt(i);
			switch (c) {
			case '\b':
				sb.append("\\b");
				break;
			case '\t':
				sb.append("\\t");
				break;
			case '\n':
				sb.append("\\n");
				break;
			case '\f':
				sb.append("\\f");
				break;
			case '\r':
				sb.append("\\r");
				break;
			default:
				sb.append(c);
			}
		}

		return sb.toString();
	}

	private  StringUtils();

}