数组的大小和长度

#include<stdio.h>

int main()
{
	int a[] = {1,2,3,4};
	printf("%d
",sizeof(a)); //16
	printf("%d
",sizeof(a+0));//4
	printf("%d
",sizeof(*a)); //4
	printf("%d
",sizeof(a+1)); //4
	printf("%d
",sizeof(a[1])); //4
	printf("%d
",sizeof(&a)); //4
	printf("%d
",sizeof(&a+1));//4
	printf("%d
",sizeof(&a[0]));//4
	printf("%d
",sizeof(&a[0]+1)); //4
	getchar();
	return 0;
}

#include<stdio.h>
#include<string.h>

int main()
{
	char arr[] = {"a","b","c","d","e","f"}; 
	printf("%d
", sizeof(arr)); //6
	printf("%d
", sizeof(arr+0));//4
	printf("%d
", sizeof(*arr));//1
	printf("%d
", sizeof(arr[1]));//1
	printf("%d
", sizeof(&arr)); //4
	printf("%d
", sizeof(&arr+1));//4
	printf("%d
", sizeof(&arr[0]+1));//4 

	printf("%d
", strlen(arr));//随机值
	printf("%d
", strlen(arr+0));//随机值
	//printf("%d
",strlen(*arr));
	//printf("%d
", strlen(arr[1]));
	printf("%d
", strlen(&arr));//随机值
	printf("%d
", strlen(&arr+1));//随机值
	printf("%d
", strlen(&arr[0]+1)); //随机值
	getchar();
	return 0;
}

#include<stdio.h>
#include<string.h>

int main()
{
	char *p = "abcdef";
	printf("%d
", sizeof(p));//4
	printf("%d
", sizeof(p+1));//4
	printf("%d
", sizeof(*p)); //1
	printf("%d
", sizeof(p[0])); //1
	printf("%d
", sizeof(&p)); //4
	printf("%d
", sizeof(&p+1)); //4
	printf("%d
", sizeof(&p[0]+1)); //4
 
	printf("%d
", strlen(p)); //6
	printf("%d
", strlen(p+1));//5
	//printf("%d
", strlen(*p));
	//printf("%d
", strlen(p[0]));
	printf("%d
", strlen(&p));//随机值
	printf("%d
", strlen(&p+1));//随机值
	printf("%d
", strlen(&p[0]+1));//5 
	getchar();
	return 0;
}

#include<stdio.h>
#include<string.h>

int main()
{
	char p[] = "abcdef";
	
	printf("%d
", strlen(p)); //6
	printf("%d
", strlen(p+1));//5
	//printf("%d
", strlen(*p));
	//printf("%d
", strlen(p[0]));
	printf("%d
", strlen(&p));//6
	printf("%d
", strlen(&p+1));//随机值
	printf("%d
", strlen(&p[0]+1));//5 
	getchar();
	return 0;
}

#include<stdio.h>
#include<string.h>

int main()
{
	int a[3][4] = {0}; 
 
	printf("%d
",sizeof(a)); //48
	printf("%d
",sizeof(a[0][0]));//4;
	printf("%d
",sizeof(a[0]));//16;
	printf("%d
",sizeof(a[0]+1));//4
	printf("%d
",sizeof(a+1)); //4
	printf("%d
",sizeof(&a[0]+1));//4
	printf("%d
",sizeof(*a)); //16
	printf("%d
",sizeof(a[3])); //16
	getchar();
	return 0;
}

总结 ：数组名只有在两种情况下代表整个数组

	1 sizeof（）括号中只放数组名时代表整个数组；

	2 取地址&数组名代表整个数组；

除此之外的所有情况均指数组首元素地址或数组地址。