我不断收到错误，Java 没有.class为该文件创建文件，而是在命令提示符下给出错误public class TotalAndAverage {public static void main (String[] arg) {    final int count = 6;    double score0 = 98.05;    double score1 = 100.00;    double score2 = 80.50;    double score3 = 62.65;    double score4 = 77.25;    double score5 = 90.93;    double total = score0 + score1 + score2 + score3 + score4 + score5;    double average = total/count;    int averageInt = (int)average;    int average2Digit = (int)(average * 100) - averageInt *100;    System.out.println("Total Score is: \t" + total);    System.out.println("Average is \t" + average);    system.out.println("Average Score is: \t" + averageInt + "." + average2Digit);}}表明错误：包系统不存在