一、数学公式:
面积=π*半径²
二、算法分析:
周长和面积都依赖半径,所以要先输入半径值,然后套用公式,计算周长和面积。 最终输出结果即可。
三、参考代码:
代码如下
#include "stdio.h"
#define Pi 3.14
void main()
{
float r,c,area
printf("请输入圆的半径:")
scanf("%f",&r)
c=2*Pi*r
area=Pi*r*r
printf("该圆的周长是%.2f,面积是%.2f\n",c,area)
}
//简单的做个import java.awt.Graphics
import java.awt.event.ActionEvent
import java.awt.event.ActionListener
import javax.swing.JFrame
import javax.swing.JPanel
import javax.swing.Timer
public class Circle extends JFrame {
public Circle(){
super()
CirclePanel panel=new CirclePanel()
add(panel, "Center")
setSize(500, 500)
setVisible(true)
}
public static void main(String[] args) {
new Circle()
}
class CirclePanel extends JPanel{
public static final double PI=Math.PI
private int degree=0
private int axisx
private int axisy
public CirclePanel(){
setSize(500, 500)
axisx=getWidth()/2
axisy=getHeight()/2
setVisible(true)
Timer timer=new Timer(10,new TimerListener())
timer.start()
}
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g)
g.fillRect(axisx, axisy, 2, 2)
g.drawOval((int)(axisx-100+5), (int)(axisy-100+5), 200, 200)
g.fillOval(-(int)(100*Math.sin(PI*degree/180))+axisx,
(int)(100*Math.cos(PI*degree/180))+axisy, 10, 10)
}
class TimerListener implements ActionListener{
public void actionPerformed(ActionEvent e) {
degree += 1
repaint()
}
}
}
}
class Circle {private int r
public Circle(int r){
this.r=r
}
public int getr(){
return r
}
public double getArea(){
return Math.PI*r*r
}
public double getCircleLength(){
return Math.PI*2*r
}
}
public class CircleComputer{
public static void main(String []args){
Circle a=new Circle(1)
System.out.println("圆半径r= "+a.getr())
System.out.println("圆面积为:"+a.getArea())
System.out.println("圆周长为:"+a.getCircleLength())
}
}