定义如下两个类:
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@interface Person : NSObject
@property (nonatomic,assign) int age;
@end
@implementation Person
@end
@interface Student : Person
@property (nonatomic,assign) int no;
@end
@implementation Student
@end
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将其转换为C++代码可见其底层实现如下:
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| struct NSObject_IMPL {
Class isa;
};
struct Person_IMPL {
struct NSObject_IMPL NSObject_IVARS;
int _age;
};
struct Student_IMPL {
struct Person_IMPL Person_IVARS;
int _no;
};
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可见子类实例对象的结构体中会包含父类的结构体，且父类的结构体存储在最前。