If you have joined your organization during the first fifteen days of the calendar month, i.e., from the 1st to the 15th (both days inclusive), you are eligible to get a day's leave for that particular month, as per general leave rules. This policy is accepted and agreed upon by the labor department as well.
Had you joined from the 16th to the end of the calendar month, i.e., the second fortnight, you are not eligible for a day's leave for that particular month. Similarly, if you resigned from the 1st to the 15th of a calendar month, you are not eligible for a day's leave for that month.
It should be the ethics of every organization that when an employee decides to leave, the HR team should show generosity to a certain extent in relieving the employee with good gestures. The goal is to ensure that the employee does not leave the organization with bitterness and grievances. This practice, however, is not mandated by labor laws.
Please proceed with the above calculations. Best wishes