深拷贝浅拷贝

所谓的深拷贝和浅拷贝只有指针才存在这样的概念。

.h文件 Person类

#import <Foundation/Foundation.h>

@interface Person : NSObject<NSCopying>
{
    int age;
    NSString *name;
}

@property(nonatomic,assign) int age;
@property(nonatomic,retain) NSString *name;

@end

.m文件

#import "Person.h"

@implementation Person

@synthesize age;
@synthesize name;

- (id)init
{
    self = [super init];
    if (self) {
        self.age=20;
        self.name=@"xiaoming";
    }
    return self;
}

- (void)dealloc
{
    [name release];
    [super dealloc];
}

-(id)copyWithZone:(NSZone *)zone
{
    Person *p=[[Person alloc]init];
    
    p.age= self.age;
//    p.name=self.name;             //浅拷贝
 
    p.name=[self.name copy];    //深拷贝
    
    return p;
}
@end

主函数

#import <Foundation/Foundation.h>
#import "Person.h"

int main(int argc, const char * argv[])
{

    @autoreleasepool {
        Person *per=[[Person alloc]init];
        NSLog(@"%d,%@",per.age,per.name);
        
        NSMutableString *str=[NSMutableString stringWithFormat:@"xiaoming"];
        per.name=str;
        per.age=21;
        NSLog(@"%d,%@",per.age,per.name);
        
        Person *per2=[[Person alloc]init];
        per2=[per copy];
        NSLog(@"%d,%@",per2.age,per2.name);

        [str appendString:@"2"];
        NSLog(@"%d,%@",per.age,per.name);
        NSLog(@"%d,%@",per2.age,per2.name);
        
        [per release];
        [per2 release];


    }
    return 0;
}

　　

转载于:https://www.cnblogs.com/ymonke/p/3237880.html