Block生命周期

#import <UIKit/UIKit.h>

typedef NSString*(^MyBlock) (NSString*,NSInteger);

@interface ViewController : UIViewController

-(MyBlock)GetDefaltBlock:(NSString*)Astr withInt:(NSInteger) Aint;
@end

#import "ViewController.h"

@interface ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad {
[super viewDidLoad];
MyBlock _b = [self GetDefaltBlock:@"Hello" withInt:123];
NSLog(@"%@",_b(@"World",456));
}

- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
}

-(MyBlock)GetDefaltBlock:(NSString *)Astr withInt:(NSInteger)Aint
{
MyBlock b = ^NSString*(NSString* Bstr, NSInteger Bint)
{
return [NSString stringWithFormat:@"STR IS %@,INT IS %ld",
[Astr stringByAppendingString:Bstr],Aint + Bint];
};
return b;
}

@end