实验6

实验任务四：

Vector.hpp

#ifndef VECTOR_HPP
#define VECTOR_HPP

#include <iostream>
#include <memory>
#include <stdexcept>

template <typename T>
class Vector
{
private:
    T *data;     // 存储动态数组的指针
    size_t size; // 数组的大小

public:
    // 构造函数，支持动态指定大小
    explicit Vector(int size = 0, T value = T()) : size(size), data(nullptr)
    {
        if (size < 0)
        {                                                        // 使用 int 类型，可以检查负数
            throw std::length_error("Size cannot be negative."); // 如果大小为负数，抛出异常
        }

        if (size > 0)
        {
            data = new T[size]; // 动态分配数组
            for (size_t i = 0; i < size; ++i)
            {
                data[i] = value; // 初始化数组元素为指定值
            }
        }
    }

    // 拷贝构造函数，实现深拷贝
    Vector(const Vector &other) : size(other.size), data(nullptr)
    {
        if (size > 0)
        {
            data = new T[size];
            for (size_t i = 0; i < size; ++i)
            {
                data[i] = other.data[i]; // 深拷贝
            }
        }
    }

    // 析构函数，释放内存
    ~Vector()
    {
        delete[] data;
    }

    // 获取数组大小
    size_t get_size() const
    {
        return size;
    }

    // at()方法，通过索引访问，检查越界，返回引用
    T &at(size_t index)
    {
        if (index >= size)
        {
            throw std::out_of_range("Index out of range.");
        }
        return data[index];
    }

    const T &at(size_t index) const
    {
        if (index >= size)
        {
            throw std::out_of_range("Index out of range.");
        }
        return data[index];
    }

    // 重载运算符[]，提供直接访问
    T &operator[](size_t index)
    {
        return data[index];
    }

    const T &operator[](size_t index) const
    {
        return data[index];
    }

    // 友元函数，用于输出Vector中的数据
    friend void output(const Vector<T> &v)
    {
        for (size_t i = 0; i < v.size; ++i)
        {
            std::cout << v.data[i] << " ";
        }
        std::cout << std::endl;
    }
};

#endif

task4.cpp

#include "Vector.hpp"
#include <iostream>
using namespace std;
void test1()
{
    using namespace std;

    int n;
    cout << "Enter n: ";
    cin >> n;

    Vector<double> x1(n);
    for (auto i = 0; i < n; ++i)
        x1.at(i) = i * 0.7;

    cout << "x1: ";
    output(x1);

    Vector<int> x2(n, 42);
    const Vector<int> x3(x2);

    cout << "x2: ";
    output(x2);
    cout << "x3: ";
    output(x3);

    x2.at(0) = 77;
    x2.at(1) = 777;
    cout << "x2: ";
    output(x2);
    cout << "x3: ";
    output(x3);
}

void test2()
{
    using namespace std;

    int n, index;
    while (cout << "Enter n and index: ", cin >> n >> index)
    {
        try
        {
            Vector<int> v(n, n);
            v.at(index) = -999;
            cout << "v: ";
            output(v);
        }
        catch (const exception &e)
        {
            cout << e.what() << endl;
        }
    }
}

int main()
{
    cout << "测试1: 模板类接口测试\n";
    test1();

    cout << "\n测试2: 模板类异常处理测试\n";
    test2();
}

实验任务五:

task5.cpp

#include <algorithm>
#include <fstream>
#include <iostream>
#include <sstream>
#include <string>
#include <vector>

using namespace std;

// 定义一个结构体来存储学生信息
struct Student
{
    string student_id;
    string name;
    string major;
    int score;
};

// 读取数据函数
vector<Student> read_data(const string &file_name)
{
    ifstream file(file_name);
    vector<Student> students;
    string line;

    // 跳过标题行
    getline(file, line);

    // 读取每一行数据
    while (getline(file, line))
    {
        stringstream ss(line);
        Student student;
        ss >> student.student_id >> student.name >> student.major >> student.score;
        students.push_back(student);
    }

    return students;
}

// 排序函数，按照专业字典序和分数降序排序
bool compare_students(const Student &a, const Student &b)
{
    if (a.major == b.major)
    {
        return a.score > b.score; // 专业相同时按分数降序排序
    }
    return a.major < b.major; // 按专业字典序排序
}

// 打印结果并保存到文件
void output_results(const vector<Student> &sorted_data, const string &output_file)
{
    // 打印到屏幕
    for (const auto &student : sorted_data)
    {
        cout << student.student_id << " " << student.name << " " << student.major << " " << student.score << endl;
    }

    // 保存到文件
    ofstream file(output_file);
    file << "学号 姓名 专业 分数\n"; // 输出标题行
    for (const auto &student : sorted_data)
    {
        file << student.student_id << " " << student.name << " " << student.major << " " << student.score << endl;
    }
}

// 主程序
int main()
{
    string input_file = "data5.txt";
    string output_file = "ans5.txt";

    // 读取数据
    vector<Student> students = read_data(input_file);

    // 排序数据
    sort(students.begin(), students.end(), compare_students);

    // 打印并保存结果
    output_results(students, output_file);

    return 0;
}