#include <iostream>
#include <assert.h>
#include <algorithm>
#include <hash_set>
#include <vector>
#include <string>
#include <assert.h>
#include <list>
using namespace std;#define abss(x) (( 1-((((x)>>(sizeof(x)*8-1))&1)<<1))*(x))
int main()
{
int a=-9;
int b=8;
int c=0;
int d=-100;
cout<<"int: "<<endl;
cout<<a<<" "<<abss(a)<<endl;
cout<<b<<" "<<abss(b)<<endl;
cout<<c<<" "<<abss(c)<<endl;
cout<<d<<" "<<abss(d)<<endl;
long long xx=-1999;
cout<<endl<<"long long "<<endl<<xx<<" "<<abss(xx)<<endl;
char ch=a+128;
cout<<endl<<"char "<<endl<<ch<<" "<<abss(ch)<<endl;
return 0;
}
1.为了兼容各种宽度的整数,采用sizeof
2.为了兼容右移操作时,左边补0还是补符号位的不同,右移之后与1做与操作
BITMAP的一个实现:
class BitMap
{
public:
static const int N=1000;
BitMap(){memset(an,0,N*4);}
void SetBit(int x)
{
an[(x>>5)] |= (1<<(x%32));
}
void ClearBit(int x)
{
an[(x>>5)] &= ~(1<<(x%32));
}
int GetBit(int x)
{
return (an[x>>5] >> (x%32))&1;
}
private:
int an[N];
};