C++基础知识：C++ bitset

#include <iostream>

 

//使用bitset需要include <bitset>

#include <bitset>

 

using namespace std;

 

int main(){

    //bitset 使用整数初始化bitset

    bitset<3> bs(7);

    //输出bs各个位的值

    cout<<"bs[0] is "<<bs[0]<<endl;

    cout<<"bs[1] is "<<bs[1]<<endl;

    cout<<"bs[2] is "<<bs[2]<<endl;

    //下面的语句会抛出outofindexexception

    //cout<<"bs[3] is "<<bs[3]<<endl;

 

    //使用字符串初始化bitset

    //注意：使用string初始化时从右向左处理，如下初始化的各个位的值将是110，而非011

    string strVal("011");

    bitset<3> bs1(strVal);

    //输出各位 

    cout<<"bs1[0] is "<<bs1[0]<<endl;

    cout<<"bs1[1] is "<<bs1[1]<<endl;

    cout<<"bs1[2] is "<<bs1[2]<<endl;

    //cout输出时也是从右边向左边输出

    cout<<bs1<<endl;

 

    //bitset的方法

    //any()方法如果有一位为1，则返回1

    cout<<"bs1.any() = "<<bs1.any()<<endl;

 

    //none()方法，如果有一个为1none则返回0，如果全为0则返回1

    bitset<3> bsNone;

    cout<<"bsNone.none() = " <<bsNone.none()<<endl;

 

    //count()返回几个位为1

    cout<<"bs1.count() = "<<bs1.count()<<endl;

 

    //size()返回位数

    cout<<"bs1.size() = "<<bs1.size()<<endl;

 

    //test()返回某一位是否为1

    //flip()诸位取反

    bitset<3> bsFlip = bs1.flip();

    cout<<"bsFlip = "<<bsFlip<<endl;

    //flip(int)将某一位取反

     

    //reset()方法将各个位的值都重置为0

 

    //to_ulong

    unsigned long val = bs1.to_ulong();

 

    int j;

    cin>>j;

}