Question

C语言中怎么取十六进制的后两位数、中间两位数，以及高位数

Answer 1

设x为6位16进制数变量，lx为低两位数变量，mx为中两位数变量，hx高两位数变量，则：
lx=x&0xFF;
mx=x>>8&0xFF;
hx=x>>16&0xFF;

Answer 2

#define LSB 0 //0,1,2 bit
#define MID 15 //16,17,18 bit
#define MSB 29 //29.30.31 bit
#define MASK 0x07

int main(int argc, char *argv[])
{
unsigned int res,ib = 0xaaaaaaaa;
res = MASK & (ib >> LSB);//0,1,2 bit
printf("LSB of ib: %d = 0x%x \n",res,res);
res = MASK & (ib >> MID);//16,17,18 bit
printf("MID of ib: %d = 0x%x \n",res,res);
res = MASK & (ib >> LSB);//29.30.31 bit
printf("MSB of ib: %d = 0x%x \n",res,res);
system("PAUSE");
return 0;
}