\0为字符串结束标志，相当于数学的空集

#include <stdio.h>
int main()
{
	char arr[] = "abc";
	char arr1[] = { 'a','b','c' };
	printf("%s\n", arr);
	printf("%s\n", arr1);
	printf("%d\n", strlen(arr));
	printf("%d\n", strlen(arr1));
	return 0;
}