学点 C 语言(21): 数据类型 - 数组与指针

1. 获取数组的地址无须 &, 因为数组名本身就是个地址

   include <stdio.h>

int main(void)
{

char c = 'A';
char cs[] = "ABC";

printf("%c, %s\n", c, cs);           /* 获取字符及字符数组的内容 */
printf("%p, %p, %p\n", &c, cs, &cs); /* 获取字符及字符数组的地址, cs 与 &cs 没有区别*/

getchar();
return 0;

}

2. 数组元素的地址是连续的:

   include <stdio.h>

int main(void)
{

char cs[] = "ABC";

printf("%p\n%p\n%p\n%p\n", cs, &cs[0], &cs[1], &cs[2]);

getchar();
return 0;

}

3. 数组名所代表的地址就是第一个元素的地址:

   include <stdio.h>

int main(void)
{

char str[] = "ABC";
char *p1 = str;
char *p2 = &str[0];

printf("%p, %p\n", p1, p2);

getchar();
return 0;

}

4. 通过指针访问数组元素:

   include <stdio.h>

int main(void)
{

char str[] = "ABC";
char *p = str;

printf("%c\n", *p);
printf("%c\n", *p+1);
printf("%c\n", *p+2);

printf("\n");

printf("%c\n", *p);
printf("%c\n", *++p);
printf("%c\n", *++p);

getchar();
return 0;

}

5. 通过指针遍历数组:

   include <stdio.h>

int main(void)
{

char str[] = "123456789";
char *p = str;

int i;
for (i = 0; i < sizeof str/sizeof str[0]; i++) {
    printf("%c\n", *p);
    p++;
}

getchar();
return 0;

}

include <stdio.h>

int main(void)
{

char str[] = "123456789";
char *p = str;

while (*p != '\0') {
    printf("%c\n", *p);
    p++;
}

getchar();
return 0;

}

include <stdio.h>

include <string.h>

int main(void)
{

char str[] = "123456789";
char *p = str;

int i;
for (i = 0; i < strlen(str); i++) {
    printf("%c\n", *(p+i));
}

getchar();
return 0;

}

include <stdio.h>

int main(void)
{

int nums[] = {111,222,333,444};
int *p = nums;

int i;
for (i = 0; i < sizeof nums / sizeof nums[0]; i++) {
    printf("%d\n", *p++);
}

getchar();
return 0;

}

6. 注意: 指针+1 是根据元素大小移动一个位置

   include <stdio.h>

int main(void)
{

int nums[] = {111,222,333,444};
int *p = nums;

int i;
printf("%d\n", *p);
printf("%d\n", *(p+1));

printf("%d\n", *p+1);  /* 不是这样; 这是代表取值后再 + 1 */

getchar();
return 0;

}

7. 上面的指针其实都是数组元素的指针, 如何声明真正的数组指针呢?

   include <stdio.h>

int main(void)
{

int nums[4] = {111,222,333,444};
int (*p)[4] = &nums;      /* 注意其中的小括号 */

printf("%d\n", (*p)[1]);  /* 用起来并不方便   */
printf("%d\n", (*p)[2]);

getchar();
return 0;

}

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