将数值(整型或其他类型均可)按二进制位打印出来的方法

#include "stdafx.h"
#include <iostream>
#include <math.h>
#include <Windows.h>
using namespace std;
#define N (int)(sizeof(int)*8)

#define SLOWMETHORD

unsigned int GetCPUTickCount(){ 
    _asm 
    { 
        rdtsc; 
    } 
} 


int _tmain(int argc, _TCHAR* argv[])
{
#ifdef SLOWMETHORD
    //方法一:利用数学库函数,速度慢
    cout<<"(Slow Methord)Enter a Number:"<<endl;
    int x;
    int a[N]={0};
    int timer=0;
    cin>>x;
    cout<<"Result: "<<endl<<endl;
    timer-=GetCPUTickCount();
    for(int i=0;i<N;i++)
    {
        a[i]=(x&(int)pow(2.0,N-i-1))>>(N-i-1);
        cout<<a[i];
        if ((i+1)%4==0)
        {
            cout<<"   ";
        }
        else
        {
            cout<<" ";
        }
    }
    cout<<endl;
    timer+=GetCPUTickCount();
    cout<<"Time Cost: "<<timer<<endl;
    system("pause");
#else
    //方法二:纯位运算,速度快
    cout<<"(Fast Methord)Enter a Number:"<<endl;
    int x;
    int a[N]={0};
    int timer=0;
    cin>>x;
    cout<<"Result: "<<endl;
    timer-=GetCPUTickCount();
    for(int i=0;i<N;i++)
    {
        int r=(1<<(N-1-i));
        a[i]=(x&r)>>(N-i-1);
        cout<<a[i];
        if ((i+1)%4==0)
        {
            cout<<"   ";
        }
        else
        {
            cout<<" ";
        }
    }
    cout<<endl;
    timer+=GetCPUTickCount();
    cout<<"Time Cost: "<<timer<<endl;
    system("pause");
#endif
    return 0;
}

 

上面提供了两种方法,其实道理都是一样的.

下面给出两种方法的耗时对比(同一数值,连续运行5次求平均数):

Slow:平均16984492.8
17179440
16361088
16946448
17293256
17142232

Fast:平均16363368
16490104
17221552
17098680
13827672
17178832

 

下面给出第三种方法,效率更高.

 cout<<"(Fast Methord)Enter a Number:"<<endl;
    int x;
    int a[N]={0};
    int timer=0;
    cin>>x;
    cout<<"Result: "<<endl;
    timer-=GetCPUTickCount();
    int off;
    int result;
    for(int i=N-1;i>=0;i--)
    {
        result=0;
        __asm
        {
            MOV eax,i
            BT x, eax
            JNC labelend
            MOV result,1
labelend:
        }
        cout<<result;
        cout<<"";
    }
    cout<<endl;
    timer+=GetCPUTickCount();
    cout<<"Time Cost: "<<timer<<endl;
    system("pause");

 利用位域达到最佳性能:

struct stINT32_Bits
{
    unsigned bit00:1;
    unsigned bit01:1;
    unsigned bit02:1;
    unsigned bit03:1;
    unsigned bit04:1;
    unsigned bit05:1;
    unsigned bit06:1;
    unsigned bit07:1;
    unsigned bit08:1;
    unsigned bit09:1;
    unsigned bit10:1;
    unsigned bit11:1;
    unsigned bit12:1;
    unsigned bit13:1;
    unsigned bit14:1;
    unsigned bit15:1;
    unsigned bit16:1;
    unsigned bit17:1;
    unsigned bit18:1;
    unsigned bit19:1;
    unsigned bit20:1;
    unsigned bit21:1;
    unsigned bit22:1;
    unsigned bit23:1;
    unsigned bit24:1;
    unsigned bit25:1;
    unsigned bit26:1;
    unsigned bit27:1;
    unsigned bit28:1;
    unsigned bit29:1;
    unsigned bit30:1;
    unsigned bit31:1;    
};
union stINT32
{
    int intVal;
    stINT32_Bits bits;
};

    cout<<"(Fast Methord)Enter a Number:"<<endl;
    int x;
    int a[N]={0};
    int timer=0;
    cin>>x;
    cout<<"Result: "<<endl;
    timer-=GetCPUTickCount();
    stINT32 val;
    val.intVal=x;
    cout<<val.bits.bit00<<" "
        <<val.bits.bit01<<" "
        <<val.bits.bit02<<" "
        <<val.bits.bit03<<" "
        <<val.bits.bit04<<" "
        <<val.bits.bit05<<" "
        <<val.bits.bit06<<" "
        <<val.bits.bit07<<" "
        <<val.bits.bit08<<" "
        <<val.bits.bit09<<" "
        <<val.bits.bit10<<" "
        <<val.bits.bit11<<" "
        <<val.bits.bit12<<" "
        <<val.bits.bit13<<" "
        <<val.bits.bit14<<" "
        <<val.bits.bit15<<" "
        <<val.bits.bit16<<" "
        <<val.bits.bit17<<" "
        <<val.bits.bit18<<" "
        <<val.bits.bit19<<" "
        <<val.bits.bit20<<" "
        <<val.bits.bit21<<" "
        <<val.bits.bit22<<" "
        <<val.bits.bit23<<" "
        <<val.bits.bit24<<" "
        <<val.bits.bit25<<" "
        <<val.bits.bit26<<" "
        <<val.bits.bit27<<" "
        <<val.bits.bit28<<" "
        <<val.bits.bit29<<" "
        <<val.bits.bit30<<" "
        <<val.bits.bit31<<endl;
    timer+=GetCPUTickCount();
    cout<<"Time Cost: "<<timer<<endl;
    system("pause");
    return 0;