指针的本质

#include <stdio.h>  
int main(int argc, char *argv[])  
{  
	int a[5] = { 1, 2, 3, 4, 5 };  
	unsigned int p;  
	
	for ((int *)p = a; (int *)p < a+5; p += sizeof(*a))  
	printf("%d ", *(int *)p);  
	printf("\n");  
	return 0;  
}  

思考一下，不用unsigned int用int行不行？为什么？