< Objective-c >block

Source: Internet
Author: User

Use of blocks (block)

        //No parameter no return value        void(^message) (void) = ^{NSLog (@"Hello world!\n");                }; //have a parameter return valueNSString * (^repeat) (NSString *,int) = ^ (NSString *str,intTimes ) {nsmutablestring*result = [nsmutablestringstring];  for(intI=0; i<times; i++) {[Result appendstring:str]; }            returnresult;                };        Message (); NSString*str = Repeat (@"hello\n",3); NSLog (@"%@", str);

Blocks can be read inside block blocks, variables within the method range

Block cannot modify the read variable

If you want to modify, you must use the __block (double underscore) modifier before the variable

< Objective-c >block

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