calcpi.cpp

c#的学习资料 书上的东西 很难找到的啊

// CalcPi.cpp : Defines the entry point for the console application.
//

#include <stdio.h>
#include <windows.h>
#include <time.h>
#include <stdlib.h>
#include <math.h>

int main(int argc, char* argv[])
{
	const int throws = 10000000;
	SYSTEMTIME now;
	SYSTEMTIME end;
	GetSystemTime (&now);
	srand ((unsigned) time (NULL));
	int Inside = 0;
	for (int i = 0; i < throws; ++i)
	{
		double cx = (double) rand() / (double) RAND_MAX;
		double cy = (double) rand() / (double) RAND_MAX;
		double distance = sqrt ((cx * cx) + (cy * cy));
		if (distance < 1.0)
			++Inside;
	}
	double pi = 4 * (double) Inside / (double) throws;
	GetSystemTime (&end);
	int msStart = 1000 * 60 * now.wMinute + 1000 * now.wSecond + now.wMilliseconds;
	int msEnd = 1000 * 60 * end.wMinute + 1000 * end.wSecond + end.wMilliseconds;
	int milliseconds = msEnd - msStart;
	printf ("pi = %6f\n", pi);
	printf ("Elapsed time = %d milliseconds\n", milliseconds);
	return 0;
}