C++ bitset用法

用法见代码与注释：

#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();
    
    cout<<val<<endl;
}