实验6

task4

代码：

#pragma once
#include <iostream>
#include <stdexcept>
#include <iomanip>

// 模板类 Vector 的定义
template <typename T>
class Vector {
public:
    // 构造函数
    Vector(int size);
    Vector(int size, T value);
    Vector(const Vector<T>& other); // 深复制构造函数

    // 析构函数
    ~Vector();

    // 成员函数
    int get_size() const; // 获取大小
    T& at(int index);     // 按索引访问元素
    const T& at(int index) const; // 常量版本
    T& operator[](int index); // 重载 []

    // 友元函数
    template <typename U>
    friend void output(const Vector<U>& vec);

private:
    int size;  // 数组大小
    T* data;   // 动态数组
};

// 构造函数
template <typename T>
Vector<T>::Vector(int size) : size(size) {
    if (size < 0) {
        throw std::length_error("Size cannot be negative.");
    }
    data = new T[size];
}

// 构造函数（指定初始值）
template <typename T>
Vector<T>::Vector(int size, T value) : size(size) {
    if (size < 0) {
        throw std::length_error("Size cannot be negative.");
    }
    data = new T[size];
    for (int i = 0; i < size; ++i) {
        data[i] = value;
    }
}

// 深复制构造函数
template <typename T>
Vector<T>::Vector(const Vector<T>& other) : size(other.size) {
    data = new T[size];
    for (int i = 0; i < size; ++i) {
        data[i] = other.data[i];
    }
}

// 析构函数
template <typename T>
Vector<T>::~Vector() {
    delete[] data;
}

// 获取大小
template <typename T>
int Vector<T>::get_size() const {
    return size;
}

// 按索引访问元素
template <typename T>
T& Vector<T>::at(int index) {
    if (index < 0 || index >= size) {
        throw std::out_of_range("Index out of range.");
    }
    return data[index];
}

template <typename T>
const T& Vector<T>::at(int index) const {
    if (index < 0 || index >= size) {
        throw std::out_of_range("Index out of range.");
    }
    return data[index];
}

// 重载运算符 []
template <typename T>
T& Vector<T>::operator[](int index) {
    return at(index);
}

// 输出 Vector 中的元素
template <typename T>
void output(const Vector<T>& vec) {
    for (int i = 0; i < vec.size; ++i) {
        std::cout << vec.data[i] << " ";
    }
    std::cout << std::endl;
}

#include <iostream>
#include "Vector.hpp"

void test1() {
    using namespace std;
    int n;

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

    Vector<double> x1(n);
    for (int 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();
}

运行截图：

 task5

代码：

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

struct Student {
    std::string name, major;
    double score;

    bool operator<(const Student& other) const {
        if (major == other.major) {
            return score > other.score; // 降序
        }
        return major < other.major; // 按字典序升序
    }
};

void load_data(const std::string& filename, std::vector<Student>& students) {
    std::ifstream file(filename);
    if (!file) {
        throw std::runtime_error("Failed to open file.");
    }

    Student student;
    while (file >> student.name >> student.major >> student.score) {
        students.push_back(student);
    }
}

void save_data(const std::string& filename, const std::vector<Student>& students) {
    std::ofstream file(filename);
    if (!file) {
        throw std::runtime_error("Failed to open file.");
    }

    for (const auto& student : students) {
        file << student.name << " " << student.major << " " << student.score << "\n";
    }
}

int main() {
    try {
        std::vector<Student> students;
        load_data("data5.txt", students);

        std::sort(students.begin(), students.end());
        save_data("ans5.txt", students);

        for (const auto& student : students) {
            std::cout << student.name << " " << student.major << " " << student.score << "\n";
        }
    } catch (const std::exception& e) {
        std::cerr << e.what() << std::endl;
    }

    return 0;
}

运行截图：