The Army has quite a selection of specialties. The Marines are straight up and the Navy is a bit different by far than all, The Air Force is much similar to the Army in rank structure but they all go to E-8 with a select few E-9's. Warrant Officers are CWO (Chief Warrant Officer)1-4. Army Air Force and Marine Officers go as such. 2nd Lt., 1st Lt., Captain, Major, Lt Colonel, Colonel, Brigadier General, Major General, Lt General, General. There have been 4 5 star Generals..or General Of The Army All Army if my history is correct. and they are: Eisenhower,Omar Bradley, Douglas Macarther and 1 Naval: Chester Nimitz...I could be wrong on the last one.
The Navy/Coast Gaurd are a selection of the following in different job specific groups such as Aviation, Machineist, or seaman, Construction (SeaBees),hospital Corpsman (also used as Marine Corp medics )As follows. E-1 Seamen recruit,E-2 seaman apprentice, E-3 Seamen, E-4 3rd class petty officer, E-5 2nd class.E-6 1st class petty officer. Then E-7 Chief Petty officer. E-8 senior chief Petty officer E-9. Master Cheif Petty officer. Warrants 1-4. Then the Ensign, Liuetnant Junior grade, leutenat, Lt commander, Commander, Captain, I don't knowe if the 1 star is reinstated..I never knew of one in my service in the 70's they used Admirals but most often a very senior CAptain was used as a squadron commander. He had a name and it escapes me after 30+ years.The 2 star adniral is a rear admiral and the 3 star is a vice admiral and 4 is an Admiral. beleive I am correct. Best wishes, Hope it helps