Pi Monte

// PiMonte.cpp : Defines the entry point for the console application.//#include "stdafx.h"#include <time.h>#include <stdlib.h>double randomBetweenPlusMinusOne(){  int k=rand()%200;//k:0~199  double m=k/100.0;//m:0~1.99  m-=1.0;//m:-1~0.99  return m;}struct Point{double x,   y;bool isInCircle(){return (x*x+y*y)<=1.0;}void SetXY(){x=randomBetweenPlusMinusOne();y=randomBetweenPlusMinusOne();}};void TestPrint(double N){double n=0;Point pt;for(int i=0;i<N;i++){pt.SetXY();if(pt.isInCircle())n++;}double piByMonte=4.0*n/N;printf("i=%d,N=%lf,piByMonte=%lf\n",i,N,piByMonte);}int main(int argc, char* argv[]){srand((unsigned)time( NULL )); double N=1e5;TestPrint(N);N=1e6;TestPrint(N);N=1e7;TestPrint(N);N=1e8;TestPrint(N);return 0;}/*i=100000,N=100000.000000,piByMonte=3.140840i=1000000,N=1000000.000000,piByMonte=3.144908i=10000000,N=10000000.000000,piByMonte=3.143233i=100000000,N=100000000.000000,piByMonte=3.142954Press any key to continue*/