strlen与sizeof异同

#include <stdio.h>

//模仿实现 strlen()
size_t strlength(const char *s)
{
	const char *sc;
	
	for(sc = s; *sc != ''; sc++)
		;
	return (sc - s);
}

int main(void)
{
	char arr[] = "Hello world";
	printf(""%s" length: %lu
",arr,(unsigned long)strlength(arr));
	printf("sizeof(arr) = %lu
",(unsigned long)sizeof(arr));

	return 0;
}

结果：

"Hello world" length: 11
sizeof(arr) = 12

结论：
strlen 不包含 ''
sizeof 是要计算空字符所占的空间的。