iOS 类簇

Person.h

#import <Foundation/Foundation.h>

NS_ASSUME_NONNULL_BEGIN

@interface Person : NSObject
@property (nonatomic,assign) NSUInteger age;

- (instancetype)personWithAge:(NSUInteger)age;
@end

NS_ASSUME_NONNULL_END

Person.m

#import "Person.h"
@interface __PersonGirl : Person

@end
@implementation __PersonGirl

@end

@interface __PersonWoman : Person

@end
@implementation __PersonWoman

@end


@implementation Person

- (instancetype)personWithAge:(NSUInteger)age
{
    if (age <= 18) {
        __PersonGirl *girl = [[__PersonGirl alloc] init];
        girl.age = age;
        return girl;
    }else {
        __PersonWoman *woman = [[__PersonWoman alloc] init];
        woman.age = age;
        return woman;
    }
}

@end

TestCode

#import "ClassClusterViewController.h"
#import "Person.h"
@interface ClassClusterViewController ()

@end

@implementation ClassClusterViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    Person *person1 = [[Person alloc] personWithAge:15];
    Person *person2 = [[Person alloc] personWithAge:30];
    NSLog(@"age:%lu,class:%@",(unsigned long)person1.age,[person1 class]);
    NSLog(@"age:%lu,class:%@",(unsigned long)person2.age,[person2 class]);
}

@end

打印结果
2021-07-14 14:19:16.392992+0800 TestUI[39422:1747234] age:15,class:__PersonGirl
2021-07-14 14:19:16.393149+0800 TestUI[39422:1747234] age:30,class:__PersonWoman