The relationship between the C language pointer and the function

One:

function and pointer relationships:

1) Pointer to function

2) pointers as arguments to functions

int max (int *p1,int *p2) {

}

1) An argument can be a pointer

2) can also be an array name of an array of the same type as the formal parameter

3) The return value is a function of the pointer:

Pointer functions

char* function name () {

return address

}

The return value is a string pointer

char * Test () {

return "XXXX";

}

char * TEST2 () {

Char ch= ' a ';

Return &ch;

}

Two: pointers to functions:

1) Pointer to function

function in memory will be divided into a separate area of memory, function name represents the memory of the functions of the first address

Represents the first memory address: Array name variable name Function name structure body name

2) Function Pointers:

Pointer variable to hold the address of the function

Format:

int max (int x,int y) {

Return x>y?x:y;

}

int sum (int x,int y) {

return x+y;

}

int * Getmax (int x,int y) {

Return x>y?&x:&y;

}

The format of the Declaration

int max (int x,int y);

To eject a function pointer by declaring

return value type (* pointer variable name) (parameter of function);

Defines a function pointer variable p,p can point to all return values that are int,

Functions with two shaping parameters

Int (*p) (int x,int y);

Note: When defining a function pointer, you can not specify the shape parametric name, but the type cannot be omitted

Int (*P1) (int,int);

3) Use of function pointers

(1) class to function pointer

Int (*p) (int x,int y);

Initialize the function pointer with the name of the function

p = sum;

(2) Calling functions with pointer variables

P (4,5);

Pros: Make function calls more flexible

The pointer to the block in OC is very similar to the function pointer

The relationship between the C language pointer and the function