/l:{0,1,2,3,4,5,6,7,8,9} s4:{7,8,9} index=sl. subset(s4);/判断s1是否为s4子集 cout<< index<end;∥结果, index=0 equal =(sl==$2); /(集合S1与S2比较相等 cout<< equal<<endl;∥为0,两集合不等//s1: {0, 1, 2, 3, 4, 5, 6, 7, 8, 9} //s4: {7, 8, 9} index = s1.subSet (s4); //判断s1是否为s4子集 cout << index << endl; //结果，index = 0 equal = (s1 == s2); //集合s1与s2比较相等 cout << equal << endl; //为0, 两集合不等 11