子集生成

#include<iostream> using namespace std;const int n=5;void A_print_subset(int n,int *A,int ch){    for(int i=0;i<ch;i++)   cout<<A[i];    cout<<" ";    int s=ch?A[ch-1]+1:1;    for(int i=s;i<=n;i++){        A[ch]=i;        A_print_subset(n,A,ch+1);    }    return ;}void B_print_subset(int n,int *A,int ch){    if(ch==n+1){        for(int i=1;i<=n;i++){            if(A[i])    cout<<i;        }        cout<<" ";        return ;    }    A[ch]=1;    B_print_subset(n,A,ch+1);    A[ch]=0;    B_print_subset(n,A,ch+1);}void C_print_subset(int n){    for(int i=1;i<(1<<n);i++){        for(int j=0;j<n;j++){            if(i&(1<<j))    cout<<j+1;        }        cout<<" ";    }    return ;}int main(){    int a[n];    for(int i=0;i<n;i++)    a[i]=i+1;    A_print_subset(n,a,0);    cout<<endl;    B_print_subset(n,a,1);    cout<<endl;    C_print_subset(n);    return 0;}