Вычисление факториала циклом

int main()
{
    int N = 5;
    int res = 1;
    for(int i = N; i > 0; --i)
    res*=i;
}

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

    int in = 7;
    int out = 1;
    for ( ; in > 1; out *= in, --in);
    cout << out;

  for (int out=1, in=7 ; in > 0; out *= in, --in)
     if (in==1) cout << out;

  for (int out=1, in=7 ; in > 0; out *= in, (--in) ? : cout << out);

#include <iostream>
#include <sstream>
#include <vector>
 
std::vector<uint8_t> nextLine(const std::vector<uint8_t> &xs)
{
  std::vector<uint8_t> ys(xs.size() + 1u, 1u);
  for (size_t i = 1u; i < xs.size(); ++i)
    ys[i] = xs[i - 1u] + xs[i];
  return ys;
}
 
std::string lineToString(const std::vector<uint8_t> &xs)
{
  std::stringstream ss;
  for (const auto &x : xs)
    ss << ((x & 1u) ? '*' : ' ');
  return ss.str();
}
 
void printSierpinskiTriangle(size_t n)
{
  std::vector<uint8_t> xs;
  for (size_t i = 0u; i < n; ++i)
    std::cout << lineToString(xs = nextLine(xs)) << "\n";
}
 
int main()
{
  printSierpinskiTriangle(128u);
  return 0;
}