C Language Pointer Advanced section: void pointers and data pointers

Conceptvoid pointer data pointer void Pointer

Basic concepts of void pointers

void means "no type", and void pointer is "No type pointer", and a void pointer can point to any type of data.
so void pointers are generally referred to as universal pointers or generic pointers, or universal pointers.

Definition form:
void *p;

* * in C language you can use a void type pointer at any time in place of another type of pointer, and a void pointer can point to a variable of any data type *
* * * * * * * * * If you want to get the variable value that it points to by using the void pointer, You need to convert the void pointer coercion type to a data type pointer that you want to match with the variable name type; * *
the Strong class type of the pointer transforms:
    void  *p;
    int *PA = (int *) p;
    And then you can manipulate the space that the original void pointer points to.
any type of pointer can be assigned to a void pointer without coercion type conversion;
    float f = 1.22f;
    float *P1 = &f;
    p = p1;//assigns float pointer to P

void pointer Applications:
a void pointer can be used when a pure memory operation is performed, or when a pointer to an unspecified type is passed;
void* memcpy (void *addr1,void *addr2,size_t N);
This function only makes a pure memory copy, and any content, including null characters, will be copied

1: Limit the function parameter
2: The qualified 3:void pointer returned to the function
is also used as a function pointer

The code looks like this:

#include <stdio.h>

int main (void)
{
    int num1 = 1;
    Char char1 = ' B ';

    /* Defines two void pointer types *
    /void *void_pointer_1;
    void *void_pointer_2;

    /* give different void pointers to different data types * *
    void_pointer_1 = &num1;
    void_pointer_2 = &char1;

    printf ("void_pointer_1:%d,void_pointer_2:%c\n", * (int *) void_pointer_1), * ((char *) void_pointer_2));

    void_pointer_2 = &num1;
    printf ("void_pointer1:%d\n", * (int *) (void_pointer_2));

    float float_1 = 1.25f;
    float* Float_pointer = &float_1;
    void* Void_float_pointer;
    /** assigns a float type pointer to a void type pointer
    /void_float_pointer = Float_pointer;

    printf ("float_pointer:%f\n", * ((float *) void_float_pointer);

    return 0;
}

Data Pointers

The concept of a data pointer:
In embedded programming, it is possible to read and write content in a specific memory, the assembly has the corresponding MOV command, and in addition to C + + programming language is basically no direct access to memory capabilities
Use of data pointers to manipulate specific memory directly through memory address

For example: in the address 0xff00ff00 corresponding memory wish to write one
unsigned int *p = (unsigned int *) 0xff00ff00;
*p = 11;

The data pointer must be cautious when manipulating specific memory, not all memory can be manipulated, you must have a better understanding of the hardware before you can operate (there may be a segment error)

Code can run, if necessary, you can directly pull down to run a bit, see how the structure of the array is initialized operation and use. Thank you for your visit, if you have written a bad place, I hope you can put forward in time, thank you for watching