block
https://www.jianshu.com/p/d01a321a3c6d
1.返回值类型为void
void (^blockName)(int)=^void(int a){};
//2.参数为void
int (^blk4)(void)=^int{return 7;};
//3.返回值和参数都是void
void(^blk5)(void)=^{};
//4.匿名block
^int(void){return 5;};
//使用typedef简化Block的声明
typedef void (^blk6)(void);
//属性:property(nonamatic,copy)blk6 imageClickBlock;
//局部位置声明一个block属性
void (^globalBlockInMemory)(int number)=^(int number){int a=0;};
globalBlockInMemory(90);