ates ▁the ▁overhead ▁of ▁a ▁separate ▁process ▁man aging ▁retain ▁counts . ▁AR C ▁and ▁manual ▁memory ▁management ▁are ▁not ▁mut ually ▁exclusive ; ▁program mers ▁can ▁continue ▁to ▁use ▁non - AR C ▁code ▁in ▁AR C - enabled ▁projects ▁by ▁dis abling ▁AR C ▁for ▁individual ▁code ▁files . ▁Xcode ▁can ▁also ▁attempt ▁to ▁automatically ▁upgrade ▁a ▁project ▁to ▁AR C . ▁ ▁AR C ▁was ▁introduced ▁in ▁LL VM ▁ 3 . 0 . ▁This ▁transl ates ▁to ▁X Code ▁ 4 . 2 ▁( 2 0 1 1 ), ▁or ▁Apple ▁LL VM ▁compiler ▁ 3 . 0 . ▁ ▁Liter als ▁Ne XT ▁and ▁Apple ▁Ob j - C ▁run times ▁have ▁long ▁included ▁a ▁short - form ▁way ▁to ▁create ▁new ▁strings , ▁using ▁the ▁literal ▁syntax ▁@" a ▁new ▁string ", ▁or ▁drop ▁to ▁Core Foundation ▁constants ▁k CF Boolean True ▁and ▁k CF Boolean False ▁for ▁NS Number ▁with ▁Boolean ▁values . ▁Using ▁this ▁format ▁saves ▁the ▁programmer ▁from ▁having ▁to ▁use ▁the ▁longer ▁initWith String ▁or ▁similar ▁methods ▁when ▁doing ▁certain ▁operations . ▁ ▁When ▁using ▁Apple ▁LL VM ▁compiler ▁ 4 . 0 ▁( X Code ▁ 4 . 4 ) ▁or ▁later , ▁arrays , ▁diction aries , ▁and ▁numbers ▁( NS Array , ▁NS Dictionary , ▁NS Number ▁classes ) ▁can ▁also ▁be ▁created ▁using ▁literal ▁syntax ▁instead ▁of ▁methods . ▁( App le ▁LL VM ▁compiler ▁ 4 . 0 ▁transl ates ▁to ▁open ▁source ▁LL VM ▁and ▁Cl ang