实验6

实验任务4

Vector.hpp

#ifndef VECTOR_HPP
#define VECTOR_HPP


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

template <typename T>
class Vector
{
private:
    T *data;
    size_t size;

public:
    explicit Vector(int n) : size(n)
    {
        if (n < 0)
        {
            throw std::length_error("Size cannot be negative");
        }
        data = new T[size];
    }

    Vector(int n, const T &value) : size(n)
    {
        if (n < 0)
        {
            throw std::length_error("Size cannot be negative");
        }
        data = new T[size];
        for (size_t i = 0; i < size; ++i)
        {
            data[i] = value;
        }
    }

    Vector(const Vector<T> &other) : size(other.size)
    {
        data = new T[size];
        for (size_t i = 0; i < size; ++i)
        {
            data[i] = other.data[i];
        }
    }

    ~Vector()
    {
        delete[] data;
    }
    
    size_t get_size() const
    {
        return size;
    }

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

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

    template <typename U>
    friend void output(const Vector<U> &v);
};

template <typename T>
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 <iostream>
#include "Vector.hpp"

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() {
    std::cout << "²âÊÔ1: Ä£°åÀà½Ó¿Ú²âÊÔ\n";
    test1();

    std::cout << "\n²âÊÔ2: Ä£°åÀàÒì³£´¦Àí²âÊÔ\n";
    test2();
}

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实验任务5

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

class Student
{
public:
    int id;
    std::string name;
    std::string major;
    int score;

    Student(int id, std::string name, std::string major, int score)
        : id(id), name(name), major(major), score(score) {}

    void print() const
    {
        std::cout << id << "\t" << name << "\t" << major << "\t" << score << std::endl;
    }
};

bool compare(const Student &s1, const Student &s2)
{
    if (s1.major == s2.major)
    {
        return s1.score > s2.score;
    }
    return s1.major < s2.major;
}

int main()
{
    std::ifstream infile("data5.txt");
    std::ofstream outfile("ans5.txt");

    if (!infile.is_open())
    {
        std::cerr << "无法打开输入文件!" << std::endl;
        return 1;
    }

    std::vector<Student> students;
    std::string line;

    std::getline(infile, line);

    while (std::getline(infile, line))
    {
        std::istringstream iss(line);
        int id;
        std::string name, major;
        int score;

        iss >> id >> name >> major >> score;

        students.push_back(Student(id, name, major, score));
    }

    std::sort(students.begin(), students.end(), compare);

    for (const auto &student : students)
    {
        student.print();
        outfile << student.id << "\t  " << student.name << "\t  " << student.major << "\t  " << student.score << std::endl;
    }

        infile.close();
        outfile.close();

        return 0;
}

测试运行代码