C++ Print Pi

PrintPi.cpp

#include <iostream>
#include <math.h>
int main(){
  double x=sqrt(12)*(1-(1/(3*pow(3,1)))+(1/(5*pow(3,2)))-(1/(7*pow(3,3)))+(1/(9*pow(3,4)))-(1/(11*pow(3,5)))+(1/(13*pow(3,6)))-(1/(15*pow(3,7)))+(1/(17*pow(3,8))));
  std::cout<<"PI estimation\n";
  std::cout<<"Estimation of PI without precision setting is "<<x<<"\n";
  printf("Estimation PI shown with 12 decimal fraction digit is %.12f\n", x);
  std::cout<<"PI value in cmath library is "<<M_PI<<"\n";
  return 0;
}