代理，block回调DEMO

#import <Foundation/Foundation.h>
#import "Soldier.h"
#import "Commander.h"

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

Commander *shizhang=[[Commander alloc]init];
//block
//        [shizhang command];

//delegate
//        [shizhang commandForDelegate];

//selector
[shizhang command];

}
return 0;
}

#import <Foundation/Foundation.h>

@protocol killJapaneseDelegate <NSObject>

-(void)getMessage:(int)num;

@end

@interface Soldier : NSObject
//block
-(void)killGhostByCommand:(NSString *)com andBlock:(void (^)(int))block;

-(int)killGhost;

@property (strong)id<killJapaneseDelegate>delegate;
//delegate
-(void)sendMessage;

//selector

-(void)useSelector:(SEL)sel andObj:(id)obj;

@end

#import "Soldier.h"

@implementation Soldier

-(int)killGhost{
int a=0;

for (int i=1; i<=10; i++) {
a+=10;
NSLog(@"%d刀:张嘎杀了%d个鬼子",i,a);
sleep(1);
}
NSLog(@"哎呀，腰子闪了");
return a;

}

-(void)killGhostByCommand:(NSString *)com andBlock:(void (^)(int))block{

if ([com isEqualToString:@"杀鬼子"]) {
NSLog(@"收到命令，师长我一刀能杀10个!");
block([self killGhost]);
}else{

NSLog(@"你说啥，我听不懂");

}

}

-(void)sendMessage{

NSLog(@"收到命令，师长我一刀能杀10个!");

[self.delegate getMessage:[self killGhost]];
}

//selector
-(void)useSelector:(SEL)sel andObj:(id)obj{

[obj performSelector:sel];

}

@end

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

@interface Commander : NSObject<killJapaneseDelegate>

//block
-(void)command;

//delegate
-(void)commandForDelegate;

//selector
-(void)howToKillGhost;

-(void)sendSelector;

@end

#import "Commander.h"

@implementation Commander

//block

-(void)command{
Soldier *zhangga=[[Soldier alloc]init];

void (^block)(int)=^(int num){

NSLog(@"师长：才杀了%d个，还有脸回来",num);

};

[zhangga killGhostByCommand:@"杀鬼子" andBlock:block];
}

//delegate

-(void)commandForDelegate{
Soldier *zhangga=[[Soldier alloc]init];

zhangga.delegate=self;

[zhangga sendMessage];
}

-(void)getMessage:(int)num{

NSLog(@"师长：才杀了%d个，还有脸回来",num);

}

//selector
-(void)howToKillGhost{
NSLog(@"现在传你绝学，一刀杀十个");

Soldier *s=[[Soldier alloc]init];

NSLog(@"师长：才杀了%d个，还有脸回来",[s killGhost]);
}

-(void)sendSelector{
Soldier *zhangga=[[Soldier alloc]init];

[zhangga useSelector:@selector(howToKillGhost:) andObj:self];

}

@end