static char findFstNonRptChar(String str) {
		if (str.isEmpty() || str == null) {
			throw new IllegalArgumentException();
		}

		for (int i = 0; i < str.length(); i++) {
			for (int j = 0; j < str.length(); j++) {
				// Special case of when i has reached the end of the
				// string and second for loop wouldn't run
				if (i == j && i == str.length()-1) { return str.charAt(i); }
				// Don't compare char to itself
				if (i == j) { continue; }
				// Definitely repeats, try the comparing the next char
				if (str.charAt(i) == str.charAt(j)) {
					break;
				}
				else {
					// if they're the same
					if (j < str.length() - 1) {
						// Check the rest of the string
						continue;
					}
					else {
						// We reached the end and haven't found a dupe
						return str.charAt(i);
					}
				}
			}
		}
		return '\0';
	}