求一个数组的所有子数组

#include
#include
#include
using namespace std;
class Solution {
public:
vector subsets(vector& nums) {
vectorarr(1);
int len = nums.size();
for (int i = 0;i < len;i++)
{
int len2 = arr.size();
for (int j = 0;j < len2;j++)
{
vectortmp = arr[j];
tmp.push_back(nums[i]);
arr.push_back(tmp);
}
}
return arr;
}
};
int main()
{
int n = 0;
cout << "please input the lenth of the array: ";
cin >> n;
vectorarr(n);
cout << "please enter the elemt of the array: ";
for (int& a : arr)
cin >> a;
Solution s;
for (vectora : s.subsets(arr))
{
for (int b : a)
cout << b;
cout << " ";
}

return 0;

}