▁class ]); ▁ ▁This ▁intercept s ▁every ▁inv ocation ▁of ▁set Main Menu ▁to ▁NS Application . ▁ ▁# import ▁In ▁the ▁C ▁language , ▁the ▁# include ▁pre - compile ▁directive ▁always ▁causes ▁a ▁file ' s ▁contents ▁to ▁be ▁inserted ▁into ▁the ▁source ▁at ▁that ▁point . ▁Object ive - C ▁has ▁the ▁# import ▁directive , ▁equivalent ▁except ▁that ▁each ▁file ▁is ▁included ▁only ▁once ▁per ▁compilation ▁unit , ▁ob vi ating ▁the ▁need ▁for ▁include ▁gu ards . ▁ ▁Linux ▁G cc ▁Comp ilation ▁ ▁// ▁FILE : ▁hello . m ▁# import ▁< Foundation / Foundation . h > ▁int ▁main ▁( int ▁arg c , ▁const ▁char ▁* ▁arg v []) ▁{ ▁▁▁▁ ▁/* ▁my ▁first ▁program ▁in ▁Object ive - C ▁*/ ▁▁▁▁ ▁NSLog (@" Hello , ▁World ! ▁\ n "); ▁▁▁▁ ▁return ▁ 0 ; ▁} ▁ ▁# ▁Comp ile ▁Command ▁Line ▁for ▁gcc ▁and ▁Min G W ▁Comp iler : ▁$ ▁gcc ▁\ ▁▁▁▁ ▁` gn ust ep - config ▁-- obj c - flags ` ▁\ ▁▁▁▁ ▁- o ▁hello ▁\ ▁▁▁▁ ▁hello . m ▁\ ▁▁▁▁ ▁- L ▁/ G NU step / System / Library / L ibr aries ▁\ ▁▁▁▁ ▁- lob j c ▁\ ▁▁▁▁ ▁- l gn ust ep - base ▁ ▁$ ▁./ hello ▁ ▁Other ▁features ▁Object ive - C ' s ▁features ▁often ▁allow ▁for ▁flexible , ▁and ▁often ▁easy , ▁solutions ▁to ▁programming ▁issues . ▁ ▁De leg ating ▁methods ▁to ▁other ▁objects