Objective-C——基础知识4（description关键字）

Person.h文件：声明两个属性name 和 age

#import <Foundation/Foundation.h>
@interface Person : NSObject

@property (copy, nonatomic) NSString* name;
@property (assign, nonatomic) NSInteger age;
@end
1
2
3
4
5
6

Person.m文件：重写了父类NSObject的description方法，类似于C#的ToString(）方法

#import "Person.h"

@implementation Person
-(NSString*) description
{
  return [NSString stringWithFormat:@"%@ %ld", self.name, self.age];
}
@end
1
2
3
4
5
6
7
8

main.m文件：对Person的对象p，赋值两个属性，然后调用其description方法，这里直接使用NSLog(@“%@”, p)打印对象即可。

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

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

   Person *p = [[Person alloc]init];
   p.name = @"xiaoming";
   p.age = 12;
   NSLog(@"%@", p);
 }
 return 0;
}
1
2
3
4
5
6
7
8
9
10
11
12
13

输出：

2022-11-10 14:02:13.491930+0800 ClassDemo[54396:1158913] xiaoming 12
Program ended with exit code: 0
1
2