////  Person.h#import 
      
       @interface Person : NSObject@property (nonatomic, assign) int age;+ (instancetype)person;- (instancetype)initWithAge:(int)age;+ (instancetype)personWithAge:(int)age;@end
      

//  Person.m#import "Person.h"@implementation Person//提供构造方法的时候也要提供类工厂方法(API里面是这么写的)，如果是MRC还要提供antorelease.+ (instancetype)person  //类工厂方法{    return [[[self alloc] init] autorelease];}- (instancetype)initWithAge:(int)age{ //构造方法    if (self = [super init]) {        _age = age;    }    return self;}+ (instancetype)personWithAge:(int)age //类工厂方法{    /*    Person *p = [[self alloc] init];    p.age = age;    return [p autorelease];    */    return [[[self alloc] initWithAge:age] autorelease];  //self = Person；}- (void)dealloc{    NSLog(@"%s", __func__);    [super dealloc];}@end

////  main.m//  auatorelease应用场景#import 
      
       #import "Person.h"int main(int argc, const char * argv[]) {    @autoreleasepool {                Person *p = [[[Person alloc] init] autorelease];        p.age = 10;        NSLog(@"age = %i", p.age);                Person *p1 = [[[Person alloc] init] autorelease];                Person *p2 = [[[Person alloc] init] autorelease];                                                 Person *1p = [Person person];        1p.age = 10;        NSLog(@"age = %i", 1p.age);                 // 注意: Foundation框架的类, 但凡是通过类工厂方法创建的对象都是autorelease的        [[NSString alloc] init];        [NSString string];        //        [NSString alloc] initWithString:(NSString *)//        [NSString stringWithString:(NSString *)];                                                Person *p = [[[Person alloc] initWithAge:10] autorelease];        NSLog(@"age = %i", p.age);                Person *p = [Person personWithAge:10];        NSLog(@"age = %i", p.age);            }    return 0;}