用c++,现要求设计一个表示学生的类，里面有学生的三项成绩：计算机成绩、数学成绩、英语成绩，要求可以求总分、平均分、最高分、最低分，并且可以输出一个学生的完整信息，问：此类该如何设计？ 要求：1.根据题目要求设计学生类，除了成绩以外要包含学生ID、姓名、年龄 2.有一个默认无参的构造函数，和一个带参的构造函数，函数的成绩参数是缺省的 3.所有属性必须私有化 4.提供get和set方法用于访问类中的成员 5.设计输出学生信息的方法 6.编写调用测试语句

回答：好的，我了解了您的要求。以下是设计的代码：

#include <iostream>
#include <string>
using namespace std;

class Student {
private:
    string id; // 学生ID
    string name; // 学生姓名
    int age; // 学生年龄
    int computer_score; // 计算机成绩
    int math_score; // 数学成绩
    int english_score; // 英语成绩

public:
    // 默认无参构造函数
    Student() {
        id = "00000";
        name = "无名氏";
        age = 0;
        computer_score = 0;
        math_score = 0;
        english_score = 0;
    }

    // 带参构造函数
    Student(string id, string name, int age, int computer_score = 0, int math_score = 0, int english_score = 0) {
        this->id = id;
        this->name = name;
        this->age = age;
        this->computer_score = computer_score;
        this->math_score = math_score;
        this->english_score = english_score;
    }

    // get方法
    string get_id() { return id; }
    string get_name() { return name; }
    int get_age() { return age; }
    int get_computer_score() { return computer_score; }
    int get_math_score() { return math_score; }
    int get_english_score() { return english_score; }

    // set方法
    void set_id(string id) { this->id = id; }
    void set_name(string name) { this->name = name; }
    void set_age(int age) { this->age = age; }
    void set_computer_score(int computer_score) { this->computer_score = computer_score; }
    void set_math_score(int math_score) { this->math_score = math_score; }
    void set_english_score(int english_score) { this->english_score = english_score; }

    // 总分
    int get_total_score() {
        return computer_score + math_score + english_score;
    }

    // 平均分
    float get_average_score() {
        return (float)get_total_score() / 3.0;
    }

    // 最高分
    int get_highest_score() {
        int max_score = computer_score;
        if (math_score > max_score) {
            max_score = math_score;
        }
        if (english_score > max_score) {
            max_score = english_score;
        }
        return max_score;
    }

    // 最低分
    int get_lowest_score() {
        int min_score = computer_score;
        if (math_score < min_score) {
            min_score = math_score;
        }
        if (english_score < min_score) {
            min_score = english_score;
        }
        return min_score;
    }

    // 输出学生信息
    void print_info() {
        cout << "学号：" << id << endl;
        cout << "姓名：" << name << endl;
        cout << "年龄：" << age << endl;
        cout << "计算机成绩：" << computer_score << endl;
        cout << "数学成绩：" << math_score << endl;
        cout << "英语成绩：" << english_score << endl;
        cout << "总分：" << get_total_score() << endl;
        cout << "平均分：" << get_average_score() << endl;
        cout << "最高分：" << get_highest_score() << endl;
        cout << "最低分：" << get_lowest_score() << endl;
    }
};

int main() {
    Student stu("10001", "张三", 18, 88, 90, 85);
    stu.print_info();
    return 0;
}

以上就是对学生类的设计，包括默认构造函数、带参构造函数、私有属性、get和set方法等。最后，输出学生信息并对其访问方法进行测试。