C指针原理(17)-C指针基础

Posted 2021-01-24

指针本身也是一种变量，支持常用的运算。比如加、减

#include?<stdio.h>

int?main(void){

????????int?i;

????????char?x[20]="0123456789ABCDEFGHIJ";

????????for?(i=0;i<20;i++){

????????printf("x[%d]:%c
",i,x[i]);

????????}

????????char?*p_x;

????????for?(p_x=&x[0];p_x<&x[20];p_x++){

????????????????printf("%c",*p_x);

????????}

????????printf?("
");

????????for?(p_x=x;p_x<(x+20);p_x++){

????????????????printf("%u:%c
",p_x,*p_x);

????????}

????????return?1;

}

在后面增加的内容p_x直接指向了x,然后通过x++来移动指针，终止for循环的条件是p_x<(x+20)，x+20指向了数组的结尾处后面的内存位置，这个内存位置永远不会被访问，所以这样引用是安全的。

最后这段代码将每个字符的内存地址以及字符本身输出.

[email protected]:~?%?make?clean

rm?mytest

[email protected]:~?%?make

cc?test3.c?-o?mytest

[email protected]:~?%?./mytest

...........

...........

4294957776:0

4294957777:1

4294957778:2

4294957779:3

4294957780:4

4294957781:5

4294957782:6

4294957783:7

4294957784:8

4294957785:9

4294957786:A

4294957787:B

4294957788:C

4294957789:D

4294957790:E

4294957791:F

4294957792:G

4294957793:H

4294957794:I

4294957795:J

[email protected]:~?%?