两道java入门，求解答

1、输入班级人数，输入每一个学生成绩，输入总成绩，平均分，最高分，最低分，不及格人数

2、请输入参与抽奖人数，输入抽奖人员姓名，输出中奖者

第一题

import java.util.Arrays;
import java.util.Scanner;

public class Test {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        System.out.println("请输入班级人数：");
        int n = sc.nextInt();

        int[] arr = new int[n];
        int sum = 0, a = 0;
        System.out.println("请继续输入学生成绩：");
        for (int i = 0; i < n; i++) {
            System.out.println("第" + (i + 1) + "个学生成绩为：");
            arr[i] = sc.nextInt();

            //总分
            sum += arr[i];

            //不及格
            if (arr[i] < 60) {
                a++;
            }
        }

        System.out.println("班级总成绩为：" + sum);
        System.out.println("班级平均分为：" + sum * 1.0 / n);
        Arrays.sort(arr);
        System.out.println("最高分为：" + arr[n-1]);
        System.out.println("最低分为：" + arr[0]);
        System.out.println("不及格人数：" + a);
    }
}

第二题

import java.util.Random;
import java.util.Scanner;

public class Test {
    public static void main(String[] args) {
        System.out.println("请输入抽奖人数：");
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();

        System.out.println("请继续输入参与抽奖人员姓名：");
        String[] arr = new String[n];
        for (int i = 0; i < n; i++) {
            System.out.println("请输入第" + (i + 1) + "个姓名：");
            arr[i] = sc.next();
        }

        Random r = new Random();
        int a = r.nextInt(5);
        System.out.println("恭喜：" + arr[a] + "抽到了大奖劳斯莱斯5元代金卷！！！");
    }
}

package test;

import java.util.Scanner;

public class test {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
System.out.println("请输入班级人数：");
int a = sc.nextInt();
int sum = 0;
int count = 0;
int max = 0;
int min = 100;
float avg=0;
int[] arr = new int[a];
System.out.println("请继续输入学生成绩：");
for (int i = 0; i < arr.length; i++) {
System.out.println("第" + (i+1) + "个学生成绩为：");
arr[i] = sc.nextInt();
sum+=arr[i];
if (max<arr[i]){
max = arr[i];
}
if (min>arr[i]){
min = arr[i];
}
if(arr[i]<60){
count++;
}
}
avg=sum/a;
System.out.println("班级总成绩为:"+sum);
System.out.println("班级平均分为:"+avg);
System.out.println("最高分为:"+max);
System.out.println("最低分为:"+min);
System.out.println("不及格人数为:"+count);
}
}