标签：c 指针
指针初步：
#include <stdio.h>
int main()
{
int i = 10;
int *p1 = &i;
printf("*p1 = %d \n",*p1);
}
root@ubuntu:~/pointer# gcc main.c ;./a.out
*p1 = 10#include <stdio.h>
int main()
{
int i = 10;
int *p1 = NULL;
p1 = &i;
printf("*p1 = %d \n",*p1);
}
root@ubuntu:~/pointer# gcc main.c ;./a.out
*p1 = 10#include <stdio.h>
int main()
{
int i = 10;
int *p1 = NULL;
p1 = &i;
*p1 = 20;
printf("*p1 = %d \n",*p1);
}
root@ubuntu:~/pointer# gcc main.c ;./a.out
*p1 = 20野指针
#include <stdio.h>
int main()
{
int *p3 ; //未初始化的指针，野指针,
*p3 = 10; //gcc 编译不通过:Segmentation fault (core dumped)
}
root@ubuntu:~/pointer# gcc main.c
Segmentation fault (core dumped)空指针类型，强转指针
#include <stdio.h>
int main()
{
int i = 10;
void *p;
p = &i;
printf("*p = %d\n",*(int *)p);
// (int *)p 把p强转为 int 类型的指针
}
root@ubuntu:~/pointer# gcc main.c ;./a.out
*p = 10指针类型兼容，不兼容
#include <stdio.h>
int main()
{
int *p = NULL;
unsigned i ;
p = &i;
char c = ‘a‘;
p = &c;
}
main.c:8:11: warning: assignment from incompatible pointer type [enabled by default]
p = &c;
^数组的地址
#include <stdio.h>
int main()
{
int chunli[10] = {0};
printf("%p\n",chunli);
printf("%p\n",&chunli);
printf("%p\n",&chunli[0]);
printf("%p\n",&chunli[1]);
}
数组的名字就是数组的初始地址；
root@ubuntu:~/pointer# gcc main.c ;./a.out
0x7fffc53060c0
0x7fffc53060c0
0x7fffc53060c0
0x7fffc53060c4#include <stdio.h>
int main()
{
int chunli[10] = {2};
int *p1 = &chunli[0];
int *p2 = chunli;
printf("%d \n",*p1);
printf("%d \n",*p2);
}
p1 ,p2 指向的是同一个地址
root@ubuntu:~/pointer# gcc main.c ;./a.out
2
2指针与数组1
#include <stdio.h>
int main()
{
int chunli[10] = {2};
int *p1 = chunli;
printf("sizeof(chunli) =%ld \n",sizeof(chunli));
printf("sizeof(p1) =%ld \n",sizeof(p1));
}
// 32bit系统 一个指针占用4个字节
// 64bit系统 一个指针占用8个字节
root@ubuntu:~/pointer# gcc main.c ;./a.out
sizeof(chunli) =40
sizeof(p1) =8本文出自 “魂斗罗” 博客，请务必保留此出处http://990487026.blog.51cto.com/10133282/1772393
标签：c 指针
原文地址：http://990487026.blog.51cto.com/10133282/1772393
