4.9 sizeof运算符

练习4.28

int main()
{
	//每一种内置类型所占空间的大小
	cout << sizeof(bool) << endl;        //1个字节
	cout << sizeof(char) << endl;        //1个字节
	cout << sizeof(wchar_t) << endl;     //2个字节
	cout << sizeof(char16_t) << endl;    //2个字节
	cout << sizeof(char32_t) << endl;    //4个字节
	cout << sizeof(short) << endl;       //2个字节
	cout << sizeof(int) << endl;         //4个字节
	cout << sizeof(long) << endl;        //4个字节
	cout << sizeof(long long) << endl;   //8个字节
	cout << sizeof(float) << endl;       //4个字节
	cout << sizeof(double) << endl;      //8个字节
	cout << sizeof(long double) << endl; //8个字节

}

练习4.29

int main()
{
	long x[10];
	long* p = x;
	//数组的大小除以单个元素的大小得到数组中元素的个数
	cout << sizeof(x)/ sizeof(*x) << endl;  //10
	//指针所占的空间大小除以类型的空间大小
	cout << sizeof(p) / sizeof(*p) << endl; //1
}

练习4.30

sizeof x + y;
(sizeof x) + y; 
sizeof p->men[i];
sizeof (p->men[i]);
sizeof a < b;
(sizeof a) < b;
sizeof f();
sizeof (f());