Do ab workouts, leg workouts,chest workouts using body weight stun growth?

At a listed age of 18 the growth centers in your long bones are likely closed and further increase in height not available. A single x-ray of the wrist/hand could confirm the closure of growth centers. Unsupervised weightlifting during early growth can result in injury to growth centers, but the cited workouts at the listed age would not.

No. Exercise will not stunt your growth. For healthy diet: http://www.choosemyplate.gov/., exercise 30 minutes/day, drink enough water daily so your urine is mostly colorless, have safe sex, no tobacco alcohol weed or street drugs. Get HPV vaccine. Wish you good health! Safe sex: https://www.hopkinsmedicine.org/health/wellness-and-prevention/safer-sex-guidelines