【java】笔记10：类与对象——本章练习

题目1：

代码如下：

import java.util.Scanner;
public class Input{public static void main(String[]args){Circle c=new Circle();PassObject yuan=new PassObject();System.out.println("r"+"\t"+"times");yuan.printAreas(c,5);
}
}class Circle{
double pi=Math.PI;
double r;
public double suu(double r){
double s=pi*r*r;
return s;
}
}class PassObject{public void printAreas(Circle c,int times){
for(int i=1;i<6;i++)
{
System.out.println((double)i+"\t"+new Circle().suu(i));
}}
}

题目2：

代码如下：

import java.util.Scanner;
import java.util.Random;
public class Input{public static void main(String[]args){Scanner myScanner = new Scanner(System.in);int[][]a=new int[3][3];String[]b=new String[3];for(int i=0;i<3;i++){System.out.println("请输入你要出的拳（0-拳头，1-剪刀，2-布）：");int your=myScanner.nextInt();int n  =	new Tom().panduan(your);if(n==0)  your=myScanner.nextInt();Random random=new Random();int comp=random.nextInt(3);b[i]=new Tom().sit(your,comp);System.out.println("===========================");System.out.println("局数"+"\t玩家的出拳"+"\t电脑的出拳"+"\t输赢情况");System.out.println(i+1+"\t"+your+"\t\t"+comp+"\t\t"+b[i]);System.out.println("===========================");a[i][0]=i+1;a[i][1]=your;a[i][2]=comp;}System.out.println("局数"+"\t\t玩家的出拳"+"\t电脑的出拳"+"\t输赢情况");for(int i=0;i<3;i++){for(int j=0;j<3;j++){System.out.print(a[i][j]+"\t\t");}System.out.print(b[i]);System.out.println();}}
}
class Tom{public String sit(int your,int comp){if(your==0&&comp==2) return "你赢了";else if(your==1&&comp==0) return "你赢了";else if(your==2&&comp==1) return "你赢了";else if(your==comp) return "平局";else return "你输了";}public int panduan(int num){if(num>2||num<0){System.out.println("你的输入有误，请输入0-2之间的数");return 0;}else return 1;}}

结果如下：