用Java计算PI逼近
我试图写一个近似PI值的代码。 我正在做的是:用Java计算PI逼近,java,pi,Java,Pi,我试图写一个近似PI值的代码。 我正在做的是: 在矩形内画圆 在矩形和圆形内绘制随机点 计算rect/cicle之间的比率 计算4/比率 那应该是圆周率 这是我的代码: import java.awt.Color; import java.awt.Frame; import java.awt.Graphics; import java.awt.Point; import java.awt.event.WindowAdapter; import java.awt.event.Wind
- 在矩形内画圆
- 在矩形和圆形内绘制随机点
- 计算rect/cicle之间的比率
- 计算4/比率
- 那应该是圆周率
import java.awt.Color;
import java.awt.Frame;
import java.awt.Graphics;
import java.awt.Point;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.util.ArrayList;
import java.util.Random;
public class Main extends Frame {
int width = 800;
ArrayList<Point> list = new ArrayList<Point>();
public void points(Graphics g) {
int numPoint = 10000000;
for (int i = 0; i < numPoint; i++) {
int min = 23;
int max = 23 + width;
Random rand = new Random();
int x = rand.nextInt(width);
int y = (int) (Math.random() * (max - min + 1) + min);
Point temp = new Point(x, y);
list.add(temp);
if (inCircle(temp)) {
g.setColor(Color.green);
} else {
g.setColor(Color.blue);
}
g.drawLine(x, y, x, y);
}
}
public void paint(Graphics g) {
g.fillRect(0, 0, 1000, 1000);
int x = width / 2;
int y = width / 2 + 23;
int radius = width / 2;
g.setColor(Color.WHITE);
g.drawOval(x - radius, y - radius, radius * 2, radius * 2);
g.drawRect(0, 23, width, width);
points(g);
calculatingPI();
}
public void calculatingPI() {
double inCircle = 0;
double inRect = list.size();
for (Point p : list) {
if (inCircle(p)) {
inCircle++;
}
}
double ratio = inRect / inCircle;
System.out.print("PI is approximated to: " + 4 / ratio + " ");
}
public boolean inCircle(Point p) {
Point center = new Point(width / 2, width / 2 + 23);
return center.distance(p) <= width / 2;
}
public static void main(String[] args) {
Frame frame = new Main();
frame.addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent we) {
System.exit(0);
}
});
// circle coordinates.
frame.setSize(800, 1000);
frame.setVisible(true);
}
}
导入java.awt.Color;
导入java.awt.Frame;
导入java.awt.Graphics;
导入java.awt.Point;
导入java.awt.event.WindowAdapter;
导入java.awt.event.WindowEvent;
导入java.util.ArrayList;
导入java.util.Random;
公共类主框架{
整数宽度=800;
ArrayList=新建ArrayList();
公共空位点(图g){
int numPoint=10000000;
对于(int i=0;i 返回中心。距离(p)您使用的是整数像素。这意味着您的“圆”越小,它与真实圆的近似程度就越差。例如,这是一个3x3像素正方形内的圆:它看起来根本不是圆形的
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要获得更好的近似值,请使用double
浮点数而不是整数。使用Point2D.double
而不是point
类:
ArrayList<Point2D.Double> list = new ArrayList<>();
请注意,如果您有max-min+1
,则必须删除+1
要测试点是否在圆内,请执行以下操作:
public boolean inCircle(Point2D.Double p) {
Point2D.Double center = new Point2D.Double(width / 2d, width / 2d + 23);
return center.distance(p) <= width / 2d;
}
公共布尔内圆(Point2D.Double p){
Point2D.Double center=新的Point2D.Double(宽度/2d,宽度/2d+23);
返回中心。距离(p)当然,因为采样点的坐标是整数,所以面积越大,“圆”(仅由整数点组成)越接近真圆?
public boolean inCircle(Point2D.Double p) {
Point2D.Double center = new Point2D.Double(width / 2d, width / 2d + 23);
return center.distance(p) <= width / 2d;
}