Sure, gratuity is due only after 5 or more years of service, and that too on resignation or retirement. However, every employee deposits an amount accrued annually in the hope that you'd claim it at the end of the year. This amount contributed by the employer for your gratuity every year is added to your CTC. The calculation for that is 15/26*1 (current year's gratuity).
Bonus and CTC Inclusion
Bonus will be included in your CTC only if it's a part of your compensation that you'd receive as per norms. However, many companies give a bonus to higher-paid employees as well in the name of ex-gratia, but that is included in the CTC.
Any contribution that an employer makes towards an employee, any cost that is incurred, is included in the CTC irrespective of it being a part of your salary.
Understanding Salary Components
Your basic salary is different, your take-home is different, net salary is different, and gross salary is different.
CTC = gross (basic + allowance + DA + HRA + conveyance, etc.) + statutory deductions like (PF and ESIC, as the case may be) + Contribution to medical/insurance + Bonus + Gratuity + Any LTAs (if applicable) + mobile reimbursement + medical reimbursement, etc.
Every single rupee that a company spends on the employee would be included in the CTC.
Hope this was helpful :)
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