第9章 数字处理类

9.1

package pra;
import java.util.Random;
public class Pra1 {
	public static int SumRam(int num1,int num2) {
		int sum=0;
		int j[]=new int[6];
		System.out.println("随机生成6个2~32之间的偶数:");
		for(int i=0;i<6;i++) {
			j[i]=num1+(int)(Math.random()*(num2-num1));
			if(j[i]%2==1)
				j[i]--;
			sum+=j[i];
			System.out.println(j[i]);
		}
		return sum;
	}	
	public static void main(String args[]) {
		System.out.println("其和为："+SumRam(2,32));
	}
}

9.2

package pra;
import java.text.DecimalFormat;
public class Pra1 {
	public static void Patternround(String pattern,double value) {
		DecimalFormat roundnum=new DecimalFormat();
		roundnum.applyPattern(pattern);
		System.out.println("圆的面积为："+roundnum.format(value));
	}
	public static double area(double radius) {
		return Math.PI*Math.pow(radius, 2);
	}	
	public static void main(String args[]) {
		Patternround("#.#####",area(1));
	}
}