对象和方法之间的关系

1.对象作为方法的参数

#import <Foundation/Foundation.h>

@interface Person : NSObject

{

@public

    int _age;

    NSString *_name;

}

-(void)displayPerson:(Person *) person;

@end

@implementation Person

-(void)displayPerson:(Person *) person{

    NSLog(@"名字:%@  年龄:%d",person->_name,person->_age);

}

@end

int main(){

    Person *p1 = [Person new];

    Person *p2 = [Person new];

    p1->_name = @"Star";

    p1->_age =18;

    p2->_name = @"Jack";

    p2->_age = 21;

    [p1 displayPerson:p1];

    [p2 displayPerson:p2];

}

2.对象作为方法的返回值

#import <Foundation/Foundation.h>

@interface Person : NSObject

{

@public

    int _age;

    NSString *_name;

}

-(void)displayPerson:(Person *) person;

-(Person *)changeSex:(Person *) person;

@end

@implementation Person

-(void)displayPerson:(Person *) person{

    NSLog(@"名字:%@  年龄:%d",person->_name,person->_age);

}

-(Person *)changeSex:(Person *) person{

    person->_age = 66;

    NSLog(@"名字: %@ 年龄: %d",person->_name,person->_age);

    return person;

}

@end

int main(){

    Person *p1 = [Person new];

    Person *p2 = [Person new];

    p1->_name = @"Star";

    p1->_age =18;

    p2->_name = @"Jack";

    p2->_age = 21;

    [p1 displayPerson:p1];

    [p2 changeSex:p2];

    Person *p3 = [p2 changeSex:p2];//p3和p2指向的是同一个空间

    NSLog(@"名字: %@ 年龄: %d",p2->_name,p2->_age);

}

马上要学oc了，还看不懂