#include 
    
     using namespace std;void combination ( int s,int j );int r;int num;int a[100],b[100];void main( ){   cout<<"请输入集合元素的个数: ";   cin >>num;   cout<
     
      >a[l];   cout<
      
       1)       combination(i+1,j-1);          else      {         cout<<"{";         for (int k=1;k<=r;k++)         cout<
       
        <<" ";         cout<<"}"<