[notes] notes on C language array pointer, structure + two-dimensional array pointer

In development For efficiency , Often a large continuous data space is used , Such as ： Structure , Array , Two dimensional array , And these are combined , It is another large space , In one bin A single-chip computer with an inch of gold in memory , Very precious , So we often use pointers to operate , One is the efficient use of memory space , One is the efficient operation of the code , There is another one that seems to people who don't understand , Pretend bility is dye-in-the-wood ！

Array notes

	uint8_t Change[4];
	
	Mask(&Change[sector],bit);
	void Mask(uint8_t *mask, uint8_t bit)
	{
    
		*mask |= (1 << bit);
	}

The above code makes use of C The address of the language array .

==&Change[sector]== Is an array Change Of [sector] Starting address at the beginning , And then use uint8_t *mask The pointer points to the beginning of the address , That is, perform a series of operations on this array , amount to ：

（uint8_t *mask）&Change[sector] == Change[sector] ;

The address the pointer points to , That is, the pointer takes the value of this address , The length type is uint8_t.

Take this as an extension ：

	uint8_t Change[4];
	
	Mask(Change,bit);
	void Mask(uint8_t *mask, uint8_t bit)
	{
    
		*mask |= (1 << bit);
	}
	// That is, to the array Change[0] First address value of , operation *mask  That's right Change Address operation .
	//uint8_t in , When mask exceed 7 in the future , That is to say, to the third party Change[1] operation , And so on .

My notes

Because it's handwritten , I won't type it , Just personal notes , There are structures inside + Two dimensional array pointer , as well as ucosiii Some contents related to the system , Patient people can study , Make a note , You can write code like this in the future , Although it's a little winding , But it's efficient .