cpp how many threads to open code example

Example 1: c++ create threads

#include <thread>
void foo() 
{
  // do stuff...
}
int main() 
{
  std::thread first (foo);
  first.join();
}

Example 2: multiple threads cpp

#include <iostream>
#include <threads>
#include <vecotr>

std::vector<std::thread*> threads;

for(int i = 0; i < x; i++)
{
  threads.push_back(new std::thread(func));
}