C Language 12th round: Another talk about pointers

C Language 12th round: A second talk on pointers

"Learning goals"

1. Array of pointers

2. Array pointers

3. Function pointers

(1) Array of pointers

Array of pointers: first it is an array, the elements of the array are pointers, and the array takes up the number of bytes by the array itself

Decided. It is the abbreviation for "array of stored pointers"

Such as:

Defines a pointer to the array named PTR, which contains 10 data that points to type int

int *ptr[10]; Array of pointers, int* modifying the contents of an array

Program

#include <stdio.h> void print_error (int n); int main (void) {         inti;                 for (i= 0; i< 4; i++)         {                   print_error (i);         }                 Putchar (10); printf ("\ n");           return 0; } void Print_error (int i) {         //defines an array containing 4 data pointers to type int         char*error[]= {                           "Cann ' t openfile\n",                                                "read error \ n ",                                                " Write error\n ",                                                " Media failure\n "                        };                          printf ("%s", error[I]);                 

(2) Array pointers

Array pointer: First it is a pointer to an array. The 3 2-bit system will always be 4 bytes,

As to how many bytes it points to the array, do not know. It is the abbreviation for "pointers to arrays".

Format: Type (* identifier) []

int (*p) [5];

#include <stdio.h> void print (char (*PTR) [ten], int n)//array pointer as parameter {         inti;                 for (i= 0; i< N; i++)         {                   printf ("%s\n", * (ptr+ i));         }                 return;} int main (void) {         charname[3] []= {                                  "Zhangsan",                                                                            "Lisi",                                                                           "Wangwu"                                };         Print (name, 3);  Print           return 0;}

(3) Function pointers

Function pointer: is a pointer to a function.

Format: Type (* identifier) ();

Program

#include <stdio.h>//using pointer parameters//function: Two number exchange void swap (int *a, int *b); int main (void) {  int n=;  int m=;   The first pointer function, the return type void,f is the function pointer  void (*F) ();      F=swap; F points to swap. Note: The type must match    printf ("Pre-swap: n=%d m=%d\n", N, m);    if (n< m)//If n< m, swap   {        f (&n, &m);   }    printf ("After Exchange: n=%d m=%d\n", N, m);          return 0;   } void swap (int *a, int *b) {         inttemp;                 Temp=*a;         *a=*b;         *b=temp;           return;   }

Operation Result:

before Exchange : n=10 m=

after Exchange : n=20 m=

"Smile at the Fingertips" error is unavoidable, hope to get everyone's correction ^ ^

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C Language 12th round: Another talk about pointers