C++位运算

本文代码主要是对《程序员面试宝典(第四版)》中第12章位运算与嵌入式编程章节的位运算进行学习，实验检测了自己的理解。

#include <iostream>
#include <stdio.h>

using namespace std;

// 1
struct a
{
	int x : 1;
	int y : 2;
	int z : 3;
};

//2
#define BIT_MASK(bit_pos) (0x01<<(bit_pos))
int Bit_Reset(unsigned int *val, unsigned char pos)
{
	if (pos >= sizeof(unsigned int) * 8)
	{
		return 0;
	}
	*val = (*val & ~BIT_MASK(pos));
	return 1;
}

//3
#define MAX 255
typedef short Int16;
struct B
{
public:
	int m_iNum;
};

int main()
{
	//位制转换
	cout << "****位制转换****" << endl;
	printf("%f \n", 5);
	printf("%f \n", 5.01);

	printf("%d \n", 5.01);
	printf("%d \n", 5);

	cout << 5 << endl;
	cout << 5.01 << endl;
	cout << endl;

	cout << "****结构体位制****" << endl;
	a d;
	cout << "&d = " << &d << endl;
	d.z = d.x + d.y;
	cout << "d.x = " << d.x << endl;
	cout << "d.y = " << d.y << endl;
	cout << "d.z = " << d.z << endl;
	cout << "sizeof(d) = " << sizeof(d) << endl;
	cout << endl;

	cout << "****比特位掩膜****" << endl;
	unsigned int x = 0xffffffff;
	unsigned char y = 4;
	Bit_Reset(&x, y);
	cout << /*hex <<*/ x << endl;
	cout << endl;

	cout << "****const_cast****" << endl;
	B b0;
	b0.m_iNum = 100;
	const B b1 = b0;
	//b1.m_iNum = 100;  // error !
	cout << "b0.m_iNum = " << b0.m_iNum << " " << "b1.m_iNum = " << b1.m_iNum << endl;
	const_cast<B&>(b1).m_iNum = 200; // const_cast去掉b1的const属性，并重新赋值200
	cout << "b0.m_iNum = " << b0.m_iNum << " " << "b1.m_iNum = " << b1.m_iNum << endl;
	cout << endl;

	return 0;
}