Question

用java语言绘制正弦曲线

老师要求我们用正弦java语言编写一个正弦曲线图像，并且能够随机变换。

请各位帮忙! 非常着急！
谢谢！

Answer 1

很简单，程序写给你，给分：

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import java.awt.*;

import javax.swing.JFrame;

import java.util.Random;

import java.text.DecimalFormat;

public class SinDemo extends JFrame {

        private double cx = 1, cy = 1;

        private double toCx = 1, toCy = 1;

        private Random rnd = new Random();

        private DecimalFormat df = new DecimalFormat("0.00");

        private SinDemo () {

                super("Sin-Demo");

                setSize(600, 600);

                setLocationRelativeTo(null);

                setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

                setVisible(true);

                run();

        }

        private int translateX (double x) {

                return (int)(x*getWidth()/Math.PI/4 + getWidth()/2);

        }

        private int translateY (double y) {

                return (int)(getHeight()/2 - y*getWidth()/Math.PI/4);

        }

        private double sin (double x) {

                return (cy * Math.sin(cx * x));

        }

        @Override

        public void paint (Graphics g) {

                super.paint(g);

                g.setColor(Color.BLUE);

                g.drawString("y = " + df.format(cx) + " * sin( " + df.format(cy) + " * x)", 50, 50);

                g.setColor(Color.LIGHT_GRAY);

                g.drawLine(0, getHeight()/2, getWidth(), getHeight()/2);

                g.drawLine(getWidth()/2, 0, getWidth()/2, getHeight());

                g.setColor(Color.BLACK);

                for (double i=-Math.PI/cx; i<Math.PI/cx; i+=0.1)

                        g.drawLine(translateX(i), translateY(sin(i)),

                                translateX(i+0.1), translateY(sin(i+0.1)));

        }

        public void run () {

                while (true) {

                        if (Math.abs(cx - toCx) < 0.1) {

                                toCx = rnd.nextDouble()*2;

                                toCy = rnd.nextDouble()*2;

                        }

                        cx += (toCx - cx)/50;

                        cy += (toCy - cy)/50;

                        paint(getGraphics());

                        try {

                                Thread.sleep(80);

                        } catch (InterruptedException ie) {}

                }

        }

        public static void main (String args[]) {

                new SinDemo();

        }

} 

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再给你一个截图：

Answer 2

你去找找thinking in java第四版
gui部分有一个话正弦曲线的，
而且可以有slider控制曲线变换