实训三

1、。

import java.util.*;
public class num3 {

    public static void main(String[] args){
        int a[];
        a = new int[5];
        
        for(int i=0;i<5;i++){
            a[i]=(int)(Math.random()*55+1);
            System.out.println(a[i]);
        }
    }
}

2。 

import java.text.SimpleDateFormat;
import java.util.*;
public class fate { 
    public static void main(String[] args) {
        Date date = new Date();
        System.out.println("时间:"+date);
        String strDate = date.toString();
        String year = strDate.substring(24,28);
        String month = strDate.substring(4,7);
        String day = strDate.substring(9,10);
        String hour = strDate.substring(11,13);
        String min = strDate.substring(14,16);
        String sec = strDate.substring(17,19);      
        System.out.print(year+"年");
        System.out.print(month+"月");
        System.out.print(day+"日   ");
        System.out.print(hour+"时");
        System.out.print(min+"分");
        System.out.println(sec+"秒");
      //2,获取当前系统时间，运用subString（）方法，显示年份。
        SimpleDateFormat dateformat1=new SimpleDateFormat("yyyy年");
        String a1 = dateformat1.format(new Date());
        System.out.println("时间："+a1);
      //3,使用Calendar类显示当前日期。
        Calendar a2 = Calendar.getInstance();      
        System.out.print(a2.get(Calendar.YEAR)+"年");
        System.out.print((a2.get(Calendar.MARCH)+1)+"月");
        System.out.print(a2.get(Calendar.DATE)+"日");
        System.out.print(a2.get(Calendar.HOUR)+":");
        System.out.print(a2.get(Calendar.MINUTE)+":");
        System.out.print(a2.get(Calendar.SECOND));      
    }
}

3。

import java.util.*;
public class fate { 
    public static void main(String[] args) {
        ArrayList a1 = new ArrayList();
        a1.add("月");
        a1.add("火");
        a1.add("水");
        a1.add("木");
        a1.add("金");
        a1.add("土");
        a1.add("日");
        int i;
        Scanner c = new Scanner(System.in);     
        System.out.println("输入星期数");
        i = c.nextInt();
        System.out.println(a1.get(i-1)+"曜日");
    }
}

实训三

原文：https://www.cnblogs.com/abcd609553/p/10986579.html