关于无符号数的编码

看了无符号数的编码:

#include 

typedef unsigned char* byte_pointer;

void show_bytes(byte_pointer start, size_t len) {
	int i;
	for (i = 0; i < len ; i++) {
		printf("%.2x ", start[i]);
	}
	printf("\n");
}

void showit(unsigned int x) {
	show_bytes((byte_pointer)&x, sizeof(x));
}

void showit(int x) {
	show_bytes((byte_pointer)&x, sizeof (x));
}

int main()
{
	unsigned int x= 12345;
	int y = 12345;
	showit(x);
	showit(y);
	return 0;
	}

结果是一样的.那计算机不是按照补码运算的吗.怎么区别有无符号呢?费解啊...