#include <stdio.h>

#include <stdlib.h>

unsigned int fit_block_size(unsigned int size)

{

unsigned int i = 10;

size = (size>>10);

for(; size; i++, size = (size>>1));

unsigned int j = 1 << (i < 10 ? 10 : i);

return j;

}

void show8_11(int var)

{

int num, mask;

num = var;

num >>= 8; /*右移8位，将8～11位移到低4位上*/

mask = ~ ( ~0 << 4); /*间接构造1个低4位为1、其余各位为0的整数*/

printf("result=0x%x:mask:%d:num:%d\n", num & mask, mask, num);

}

void

swap(int x, int y)

{

x ^= y;

y ^= x;

x ^= y;

printf("x:%d:y:%d\n", x, y);

}

//获取1的个数

int Get1Nums(int i)

{

int count = 0;

int k = i;

while(k)

{

count++;

k &= (k - 1);

}

return count;

}

typedef unsigned char BYTE;

#pragma pack(push, 1)

typedef struct tagbits

{

BYTE i: 1,

i2: 1,

i3: 1,

i4: 1,

i5: 1,

i6: 1,

i7: 1,

i8: 1;

}bits;

struct bit

{

unsigned a: 5,

b: 5;

};

struct bit2

{

int a: 5;

int b: 5;

int c: 5;

};

struct bit3

{

BYTE a: 5;

BYTE b: 5;

int c: 5;

};

struct bit4

{

unsigned short i0: 2,

i1: 3,

i2: 4,

i3: 5,

: 2; // 无名段

};

#pragma pack(pop)

void opBits()

{

bits b = {0};

b.i = 1;

b.i2 = 1;

printf("b: 0x%x\n", b.i3);

}

//将int型变量a的第k + 1位清0，即a=a&~(1<<k), 0 by start

#define SetBitTo0(a, k) (a)&~(1<<k)

// 将int型变量a的第k位置1， 即a=a|(1<<k)

#define SetBitTo1(a, k) (a) | (1<<k)

#define average(x, y) ((x) & (y))+(((x) ^ (y))>>1)

#define lmove(a, b) (a) << (b)

#define rmove(a, b) (a) >> (b)

//变换符号

#define ABS(a) (~(a) + 1)

//连接字符串,用于函数的格式化参数

//inttypes.h 定义了很多这种格式

#define PRIU32 "l" "u"

// 获取系统的字长

#define OS_BITS (((int)((int *)0 + 1)) << 3)

/* int *p=NULL; //0x00000000

int *ptr = p + 1; //0x00000004

int res = (int)ptr; // 4

int myres = res <<3; //32

关键就是 p+1 后，移动了4个字节。*/

//是否为2的幂 0: 是 非零不是

#define IS_2_N(a) ((a) & (a -1))

#define IS_2_N_2(a) (((a) & (~a + 1)) == (a))

//获取类型的最大值

#define MAX_INT ((int)(~(int)0) - 2) // 只能是unsigned的

#define MAX_SIZET ((size_t)(~(size_t)0)-2)

#define __MAX_SLOT__ 16833

int main(int argc, char **argv)

{

show8_11(0x0A0C);

swap(11, 22);

opBits();

int i = 12;

i = SetBitTo0(i, 3);

printf("i: %d\n", i);

i = SetBitTo1(i, 3);

printf("i: %d\n", i);

printf("i: %d\n", average(i, i));

int j = 1;

j = lmove(j, 30);

printf("j: %d\n", j);

printf("sizeof: %d\n", sizeof(bit3));

printf("1 : %d\n", Get1Nums(3));

printf("size: %u\n", fit_block_size(1025));

int aaa = 1;

printf("change: %x\n", aaa);

printf("change: %x\n", ABS(aaa));

printf("qufan: %x\n", ~aaa);

int bbb = -1;

printf("bbb: %x\n", bbb);

printf("bbb: %x\n", bbb << 2);

printf("bbb: %x\n", bbb >> 2);

unsigned int ccc = 100;

printf("ccc: %" PRIU32 "\n", ccc);

printf("PRIU32: %s\n", PRIU32);

printf("MAX_INT: %u\n", MAX_INT);

printf("MAX_INT: %zu\n", MAX_SIZET);

printf("xxx: %d\n", 10 << 10); // 相当于 10 * 2的10幂

long uid = 1499999999;

printf("slotId: %d\n", uid & __MAX_SLOT__);

return 0;

}