The term CTC is more confusing than clarifying, CTC is only the computed cost arrived indicating the per head expenses of the organisation for its manpower, it includes not only the direct benefit which the employee gets every month so also the proportionate cost for indirect employee benefits like transport, canteen, medical, township, social clubs, associations etc., etc. The employee doesn't get these indirect benefits in hand like the employer's share of PF, the annuity paid for gratuity etc. But they are reckoned.
The eligibility for gratuity is only after completion of the required length of service and it is not paid before as pointed out above. But still is an expense borne by the company and would come into calculation of CTC. So it is only an indicative figure and what the employee actually gets as gross pay is different.