public static String arrToStr(String[] arr) {
        StringBuilder sb = new StringBuilder();
        if (arr.length % 2 == 0)
            for (int i = 0; i < arr.length; i++) {
                sb.append(arr[i]);
                if (i % 2 == 0) sb.append("\n");
                else sb.append(": ");
            }
        else 
            for (String arr1 : arr) {  sb.append(arr1).append(" "); }
        return sb.toString();
    }