13.写出运行结果:

{// test1
	char str[] = "world"; cout << sizeof(str) << ": ";
	char *p    = str;     cout << sizeof(p) << ": ";
	char i     = 10;      cout << sizeof(i) << ": ";
	void *pp   = malloc(10);  cout << sizeof(p) << endl;
}

6：4：1：4

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14.写出运行结果:

{// test2
	union V {
		struct X {
			unsigned char s1:2;
			unsigned char s2:3;
			unsigned char s3:3;
		} x;
		;unsigned char c;
	} v;
	v.c = 100;
	printf("%d", v.x.s3);
}

3

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15.用C++写个程序，如何判断一个操作系统是16位还是32位的？不能用sizeof()函数

A1:

16位的系统下，

int i = 65536;

cout << i; // 输出0；

int i = 65535;

cout << i; // 输出-1；