// ukazatel na funkci
#include<iostream>
#include<cmath>
using namespace std;
int main(void){
  double x = M_PI/6.;  // 30deg
  double (*p_fce)(double);
 
  p_fce = sin;
  cout << p_fce(x) << endl;
  
  p_fce = cos;
  cout << p_fce(x) << endl;
}