JAVA关于顺序表操作的问题

public class StudScore {

    String name;
    int studentNo;
    double score;

    public StudScore() {

    }

    public StudScore(String name, int studentNo, double score) {
        this.name = name;
        this.studentNo = studentNo;
        this.score = score;
    }

    public void setName(String name) {
        this.name = name;
    }

    public void setStudentNo(int studentNo) {
        this.studentNo = studentNo;
    }

    public void setScore(double score) {
        this.score = score;
    }

    public String getName() {
        return name;
    }

    public int getStudentNo() {
        return studentNo;
    }

    public double getScore() {
        return score;
    }

    public String toString() {
        return name + "," + studentNo + "," + score;
    }

}

public interface StudOPeration {

    void add(StudScore node);

    void listAll();

    void search(int index);

    int getCounts();

    void delete(int index);

    void search(String name);

}

public class ArrStudent implements StudOPeration {

    StudScore stud[] = new StudScore[5];
    int count = 0;
    String name;

    public ArrStudent() {

    }

    public ArrStudent(int size) {

    }
    @Override
    public void add(StudScore node) {
        int i = count;
        stud[i] = node;
        count++;

        if (count == stud.length) {
            System.out.println("存储空间已满");
        }
    }
    @Override
    public void listAll() {
        for (int i = 0; i < count; i++) {
            System.out.print(stud[i].name + "\t");
            System.out.print(stud[i].studentNo + "\t");
            System.out.println(stud[i].score);
        }
    }
    @Override
    public void search(int index) {
        if (index <= count && index > 0) {
            System.out.println("您查找信息是：" + stud[index - 1]);
        } else {
            System.out.println("输入的序号无效！！");
        }
    }
    @Override
    public int getCounts() {

        return 0;
    }
    @Override
    public void delete(int index) {

    }
    @Override
    public void search(String name) {
    }
}