Use of block in OC

Block is a data type used to hold a piece of code

Defines a pointer to a function very much like

Int (*MYP) (Int,int) {

}

typedef int (*MYP) (int,int);

Block Flag ^

Block is like a function.

L can save the code

L have return value

L Tangible parameters

L Call the same way

Attention

L default block cannot modify external local variables

L can modify local variables in block code after adding _block to local variables.

1. Define a block type

return value type (^block type name) (parameter type,.....)

Int (^MYB) (int,int); /int (^MYB) ();

2. Assigning a value to a defined type

MyB = ^ (int a, int b)

{

}

MyB = ^{

}

1, 2 together is

Int (^myblock) (int,int) = ^ (int a,int b) {

};

typedif Int (^MYB) (int, int);

Use of block in OC