Zadanie 2 całe dobrze

#include <iostream>
#include <cstdio>
#include "time.h"
#include <cstdlib>
#include <windows.h>
#include <cmath>

using namespace std;
using namespace std;
int main()
{
        int a,i,k,l;
        char b;
  do{
       cout << "Podaj dlugosc podstawy trojkata: ";
                cin >> a;
  }


        while (a<1 || a>21 || a%2==0);

cout<<"dobrze"<<endl;
                cout << "Podaj znak: ";
                 cin >> b;





        for (k=1; k<a+1; k=k+2)
        {
                for (l=1; l<a-k; l=l+2)
                {
                        cout << " ";
                }
                for (i=1; i<k+1; i++)
                {
                         cout << b;
                }
                         cout << endl;
        }




cin.ignore();
getchar ();
return 0;
}