Can't fix this simple thing for an hours

Question

What it should do:
*
***
*****
*******
*******
*****
***
*

#include <iostream>
using namespace std;
int main()
{
int lines;
cin >> lines;

for (int end = 0; end < lines;
end++) { //lines

for (int vzostupne = 0; vzostupne < end * 2 + 1; vzostupne++) {
cout << "*"; }
cout << endl; }

int cislo = lines * 2 + 1;

for (int end = 0; end < lines;
end++) { //lines

for (int zostupne = 0; zostupne > cislo * 2 + 1;
zostupne--) {
cout << "*"; }
cout << endl; }

return 0;
}

Answer 1

https://code.sololearn.com/cax8WL0KPrKt/?ref=app

Answer 2

Thanks!