习题2-3

#include<iostream>
using namespace std;
int main()
{
 int n;
 cin >> n;
 for (int i = 1; i <= n; i++)
 {
  for (int j = 1; j < i; j++) {
   cout << "  ";
  }
  for (int k = 0; k <2 * (n - i ) + 1; k++)
  {
   cout << "# " ;
  }
  cout << endl;
 }
 return 0;
}