private void add(String str){
		if(strList.isEmpty()){
			strList.add(str);
		}
		else{
			for(int i = 0; i < strList.size(); i++){
				if(str.compareTo(strList.get(i)) <= 0){
					//Add str to the ith element and move the latter elements by one.
					strList.add(i, str);
					break;
				}
			}
		}
	}