```java package net.zhaoxuyang.common.algorithm.random; /** * 數值隨機化算法 * * @author zhaoxuyang */ public class Numerical { public static void main(String[] args) { System.out.println(calculatePI(1)); System.out.println(calculatePI(10)); System.out.println(calculatePI(100)); System.out.println(calculatePI(1000)); System.out.println(calculatePI(100000)); System.out.println(calculatePI(1000000)); System.out.println(calculatePI(10000000)); System.out.println(calculatePI(100000000)); System.out.println(calculateDefiniteIntegral(100000000)); } /** * 計算π的值 * @param n * @return */ static double calculatePI(int n) { double x; double y; int k = 0; for (int i = 1; i <= n; i++) { x = Math.random(); y = Math.random(); if ((x * x + y * y) <= 1) { k++; } } return 4.0 * k / n; } /** * 計算定積分(y=x^2) * @param n * @return */ static double calculateDefiniteIntegral(int n) { int k = 0; double x; double y; for (int i = 0; i <= n; i++) { x = Math.random(); y = Math.random(); double fx = 2 * x; if (y <= fx) { k++; } } return 1.0 * k / n; } } ```