第7节 一个编程实例
例子:
- 编写的程序用于计算圆的面积;
- 接受用户的输入,读取半径值;
- 利用下面的公式计算面积:
Area = radius * radius * 3.14159 - 显示面积area
//ComputeArea.java: Comute the area of a circle
public class ComputeArea
{
Public static void main ( String[] args )
{
Double radius;
Double area;
System.out.println( “Welcome to Java World !!!” );
}
}
import javax.swing.JOptionPane;
public class ComputeArea
{
public static void main(String[ ] args)
{
double radius;
double area;
radius = Double.parseDouble(JOptionPane.showInputDialog("请输入半径值"));
area = radius * radius *3.14159;
JOptionPane.showMessageDialog(null,"area = "+ area);
}
}


