#include<iostream>
#include<cmath>
using namespace std;

int main(){
	double numbers[] = {0.0, 1.1, 2.2, 3.3, 4.4, 5.5};

	// return_type (*variable_name)(parameters) 
	double (*fun)(double) = tan;

	for(int i : numbers)
		cout << "fun(" << i << "): " << fun(i) << endl;
	
	return 0;
}