#include <time.h>
#include <math.h>
#include <iostream>
#include <gmpxx.h>

int main() {

	clock_t start = clock();       // get program start time

	mpz_class factorialresult;     // declare new mpz (integer) class, and new "factorialresult" variable 
	unsigned long i;               // loop variable
	
	for (i=1; i <= 500; i++)       // for loop to perform factorial on i from i=1 to 500
	{
		mpz_fac_ui (factorialresult.get_mpz_t(), i);   // perform factorial on i using GMP factorial function
		std::cout << factorialresult << " = " << i << "!" <<"\n";  //output result
	}
	
	clock_t end = clock();         // get program end time
	double time_elapsed = double(end-start)/CLOCKS_PER_SEC;  // compute elapsed time
	std::cout << "clocks per sec: " <<CLOCKS_PER_SEC <<"\n";  // display info...
	std::cout << "start: " <<start << "   end: " <<end <<"\n";
	std::cout << time_elapsed << "\n";

	return 0;

}

#include <math.h>
#include <iostream>
#include <ctime>
#include <gmpxx.h>
#include <sys/time.h>

int main() {
	
	timeval time_tod;
	gettimeofday(&time_tod, NULL);      // get start time using gettimeofday
	double t1=time_tod.tv_sec+(time_tod.tv_usec/1000000.0);
	clock_t start = clock();       // get program start time using clock

	mpz_class factorialresult;     // declare new mpz (integer) class
	unsigned long i=200000;        // number to perform factorial

	mpz_fac_ui (factorialresult.get_mpz_t(), i);   // perform factorial on i
	
	gettimeofday(&time_tod, NULL); 
	double t2=time_tod.tv_sec+(time_tod.tv_usec/1000000.0);
	
	std::cout << factorialresult << " = " << i << "!" <<"\n";  //output factorial result
	
	clock_t end = clock();         // get program end time using clock
	
	double time_elapsed = double(end-start)/CLOCKS_PER_SEC;  // compute elapsed time using clock
	double time_elapsed_timeofday = t2-t1;   // compute elapsed time using "gettimeofday"
	
	std::cout << "clocks per sec: " <<CLOCKS_PER_SEC <<"\n";  
	std::cout << "start in clock: " <<start << "   end in clock: " <<end <<"\n";
	std::cout << "Time from clock():  "<< time_elapsed << "\n";
	std::cout << "Time from ""gettimeofday()"": " << time_elapsed_timeofday <<"\n";

	return 0;

}