iOS 中方法和函数的区别

@interface Person : NSObject@property (nonatomic,copy) NSString *firstName;//方法声明- (void)run;+ (void)play;@end
@implementation Person//方法声明实现- (void)run{    NSLog(@"%s",__func__);}+ (void)play{    NSLog(@"%s",__func__);}@end
//外部函数extern void sayHi(){    printf("sayHi\n");}//内部函数static void sayHello(){    printf("sayHello");}
- (void)viewDidLoad {    [super viewDidLoad];    Person *p = [[Person alloc]init];    //方法调用      [p run];    [Person play];    //函数调用      sayHi();    sayHello();}