(持续更新中!!~)15、原来可以这样理解C语言_理解指针(2/3)数组和指针笔试题解析

目录

 2. 数组和指针笔试题解析

2.1 ⼀维数组

2.2 字符数组

2.3 ⼆维数组

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 2. 数组和指针笔试题解析

2.1 ⼀维数组

int a[] = {1,2,3,4};

printf("%d\n",sizeof(a));

printf("%d\n",sizeof(a+0));

printf("%d\n",sizeof(*a));

printf("%d\n",sizeof(a+1));

printf("%d\n",sizeof(a[1]));

printf("%d\n",sizeof(&a));

printf("%d\n",sizeof(*&a));

printf("%d\n",sizeof(&a+1));

printf("%d\n",sizeof(&a[0]));

printf("%d\n",sizeof(&a[0]+1));

2.2 字符数组

代码1：

char arr[] = {'a','b','c','d','e','f'};

printf("%d\n", sizeof(arr));

printf("%d\n", sizeof(arr+0));

printf("%d\n", sizeof(*arr));

printf("%d\n", sizeof(arr[1]));

printf("%d\n", sizeof(&arr));

printf("%d\n", sizeof(&arr+1));

printf("%d\n", sizeof(&arr[0]+1));

代码2： 

char arr[] = {'a','b','c','d','e','f'};

printf("%d\n", strlen(arr));

printf("%d\n", strlen(arr+0));

printf("%d\n", strlen(*arr));

printf("%d\n", strlen(arr[1]));

printf("%d\n", strlen(&arr));

printf("%d\n", strlen(&arr+1));

printf("%d\n", strlen(&arr[0]+1));

代码3： 

char arr[] = "abcdef";

printf("%d\n", sizeof(arr));

printf("%d\n", sizeof(arr+0));

printf("%d\n", sizeof(*arr));

printf("%d\n", sizeof(arr[1]));

printf("%d\n", sizeof(&arr));

printf("%d\n", sizeof(&arr+1));

printf("%d\n", sizeof(&arr[0]+1));

代码4： 

char arr[] = "abcdef";

printf("%d\n", strlen(arr));

printf("%d\n", strlen(arr+0));

printf("%d\n", strlen(*arr));

printf("%d\n", strlen(arr[1]));

printf("%d\n", strlen(&arr));

printf("%d\n", strlen(&arr+1));

printf("%d\n", strlen(&arr[0]+1));

代码5： 

char *p = "abcdef";

printf("%d\n", sizeof(p));

printf("%d\n", sizeof(p+1));

printf("%d\n", sizeof(*p));

printf("%d\n", sizeof(p[0]));

printf("%d\n", sizeof(&p));

printf("%d\n", sizeof(&p+1));

printf("%d\n", sizeof(&p[0]+1));

代码6： 

char *p = "abcdef";

printf("%d\n", strlen(p));

printf("%d\n", strlen(p+1));

printf("%d\n", strlen(*p));

printf("%d\n", strlen(p[0]));

printf("%d\n", strlen(&p));

printf("%d\n", strlen(&p+1));

printf("%d\n", strlen(&p[0]+1));

2.3 ⼆维数组

int a[3][4] = {0};

printf("%d\n",sizeof(a));

printf("%d\n",sizeof(a[0][0]));

printf("%d\n",sizeof(a[0]));

printf("%d\n",sizeof(a[0]+1));

printf("%d\n",sizeof(*(a[0]+1)));

printf("%d\n",sizeof(a+1));

printf("%d\n",sizeof(*(a+1)));

printf("%d\n",sizeof(&a[0]+1));

printf("%d\n",sizeof(*(&a[0]+1)));

printf("%d\n",sizeof(*a));

printf("%d\n",sizeof(a[3]));

        数组名的意义：

1. sizeof(数组名)，这⾥的数组名表⽰整个数组，计算的是整个数组的⼤⼩

2. &数组名，这⾥的数组名表⽰整个数组，取出的是整个数组的地址。

3. 除此之外所有的数组名都表⽰⾸元素的地址。