Objective-C-类的扩展（17-08-02）

//
//  main.m
//  OC_06类的扩展
//
//  Created by lanou3g on 17/8/2.
//  Copyright © 2017年 lanou3g. All rights reserved.
//

#import <Foundation/Foundation.h>
#import "NSString+SayHi.h"
#import "NSString+Captical.h"

int main(int argc, const char * argv[]) {
    
    [@"包包" sayHi];
    NSString *string = [@"liying" firstCharacter];
    NSLog(@"%@",string);
    
    NSString *string1 = [@"liying" changeCaptical];
    NSLog(@"%@",string1);
    
    return 0;
}

//
//  NSString+SayHi.h
//  OC_06类的扩展
//
//  Created by lanou3g on 17/8/2.
//  Copyright © 2017年 lanou3g. All rights reserved.
//

#import <Foundation/Foundation.h>

@interface NSString (SayHi)


- (void)sayHi;


@end

//
//  NSString+SayHi.m
//  OC_06类的扩展
//
//  Created by lanou3g on 17/8/2.
//  Copyright © 2017年 lanou3g. All rights reserved.
//

#import "NSString+SayHi.h"

@implementation NSString (SayHi)

- (void)sayHi {
    NSLog(@"我是%@,我是一个字符串",self);
}

@end

//
//  NSString+Captical.h
//  OC_06类的扩展
//
//  Created by lanou3g on 17/8/2.
//  Copyright © 2017年 lanou3g. All rights reserved.
//

#import <Foundation/Foundation.h>

@interface NSString (Captical)

- (NSString *)changeCaptical;
- (NSString *)firstCharacter;

@end

//
//  NSString+Captical.m
//  OC_06类的扩展
//
//  Created by lanou3g on 17/8/2.
//  Copyright © 2017年 lanou3g. All rights reserved.
//

#import "NSString+Captical.h"

@implementation NSString (Captical)

- (NSString *)changeCaptical {
    return [self capitalizedString];

}
- (NSString *)firstCharacter {
    if (self.length > 0) {
        return [[self substringToIndex:1] uppercaseString];
    }
    NSLog(@"空字符串别凑热闹");
    return nil;
}

@end

//
//  Person.h
//  OC_06类的扩展
//
//  Created by lanou3g on 17/8/2.
//  Copyright © 2017年 lanou3g. All rights reserved.
//

#import <Foundation/Foundation.h>

@interface Person : NSObject

@end

//
//  Person.m
//  OC_06类的扩展
//
//  Created by lanou3g on 17/8/2.
//  Copyright © 2017年 lanou3g. All rights reserved.
//

#import "Person.h"

@interface Person ()
@property (nonatomic, retain) NSString *age;

@end

@implementation Person

- (instancetype)init {
    self = [super init];
    if (self) {
        //私有方法通常是通过其他方法间接调用的，目的是将某一部分的代码封装起来，方便多次使用
        [self sayHi];
    }
    return self;
}

//没在.h中声明的都是私有方法
- (void)sayHi {
    NSLog(@"baobaodabaobao");
}

@end