蒙特卡罗模拟（使用随机数和概率来解决问题）

public class MonteCarloSimulation {//求出pi的值
	public static void main(String [] args)
	{
		final int NUMBER_OF_TRIALS=10000000;
		int numberOfHits=0;
		for(int i=0;i<NUMBER_OF_TRIALS;i++)
		{
			double x=Math.random()*2.0-1;
			double y=Math.random()*2.0-1;
			if(x*x+y*y<=1)
				numberOfHits++;
		}
		double pi=4.0*numberOfHits/NUMBER_OF_TRIALS;
		System.out.println("PI is "+pi);
	}
}