实验 6

实验 6

实验任务 4

// Vector.hpp

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

template <typename T>
class Vector {
public:
    // 构造函数，动态指定大小
    explicit Vector(int size) {
        if (size < 0) {
            throw std::length_error("Size cannot be negative");
        }
        _size = size;
        _data = std::make_unique<T[]>(size);
    }

    // 构造函数，指定大小并初始化值
    Vector(int size, T value) {
        if (size < 0) {
            throw std::length_error("Size cannot be negative");
        }
        _size = size;
        _data = std::make_unique<T[]>(size);
        for (int i = 0; i < size; ++i) {
            _data[i] = value;
        }
    }

    // 用已有 Vector 对象构造新的对象（深复制）
    Vector(const Vector<T>& other) {
        _size = other._size;
        _data = std::make_unique<T[]>(_size);
        for (int i = 0; i < _size; ++i) {
            _data[i] = other._data[i];
        }
    }

    // 析构函数，释放内存资源
    ~Vector() = default;

    // 获取大小
    int get_size() const {
        return _size;
    }

    // 通过索引访问元素
    T& at(int index) {
        if (index < 0 || index >= _size) {
            throw std::out_of_range("Index out of range");
        }
        return _data[index];
    }

    // 重载[]运算符
    T& operator[](int index) {
        return at(index);
    }

    // 友元函数，实现输出 Vector 类对象中的数据项
    friend void output(const Vector<T>& vec) {
        for (int i = 0; i < vec._size; ++i) {
            std::cout << vec._data[i] << " ";
        }
    }

private:
    int _size;
    std::unique_ptr<T[]> _data;
};

#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();
}

实验任务 5

#include <fstream>
#include <iostream>
#include <string>

using namespace std;

struct Student {
  int id;
  string name;
  string major;
  int score;
};

int main() {
  auto fin = ifstream("data5.txt");
  if (!fin) {
    cout << "Failed to open file." << endl;
    return 1;
  }
  string line;
  getline(fin, line);
  auto stus = vector<Student>();
  while (!fin.eof()) {
    int id, score;
    string name, major;
    fin >> id >> name >> major >> score;
    stus.push_back({id, name, major, score});
  }
  auto fout = ofstream("ans5.txt");
  for (auto &stu : stus) {
    cout << stu.id << " " << stu.name << " " << stu.major << " " << stu.score
         << endl;
    fout << stu.id << " " << stu.name << " " << stu.major << " " << stu.score
         << endl;
  }
  return 0;
}