#include <array>
#include <iostream>

constexpr std::size_t kSize = 10;

int main() {
  std::array<char, kSize * 2 + 1> buffer;
  buffer.fill(' ');
  buffer.back() = '\n';

  auto first = buffer.begin();
  auto mid = first + kSize;
  auto size = buffer.size();
  auto a = mid;
  auto b = mid;

  while (a != first) {
    --a;
    *a = '/';
    *b = '\\';
    std::cout.write(first, size);
    *b = ' ';
    *a = ' ';         
    ++b;
  }

  while (b != mid) {
    --b;
    *b = '/';
    *a = '\\';
    std::cout.write(first, size);
    *a = ' ';
    *b = ' ';         
    ++a;
  }
}