实验6 模板类、文件I/O和异常处理

1.实验任务4
Vector.hpp源代码:

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#pragma once

#include <iostream>
#include <stdexcept>
#include <algorithm> // for std::copy

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

public:
    // 构造函数
    Vector(size_t n) : size(n), data(new T[n]) {}

    // 初始化构造函数
    Vector(size_t n, const T& value) : size(n), data(new T[n]) {
        std::fill(data, data + n, value);
    }

    // 拷贝构造函数
    Vector(const Vector& other) : size(other.size), data(new T[other.size]) {
        std::copy(other.data, other.data + other.size, data);
    }

    // 析构函数
    ~Vector() {
        delete[] data;
    }

    // 禁止拷贝赋值
    Vector& operator=(const Vector&) = delete;

    // 获取大小
    size_t get_size() const {
        return size;
    }

    // 通过索引访问元素
    T& at(size_t index) {
        if (index >= size) {
            throw std::out_of_range("Index out of range");
        }
        return data[index];
    }

    // 通过索引访问元素（const 版本）
    const T& at(size_t index) const {
        if (index >= size) {
            throw std::out_of_range("Index out of range");
        }
        return data[index];
    }

    // 重载 []
    T& operator[](size_t index) {
        return at(index);
    }

    // 重载 []（const 版本）
    const T& operator[](size_t index) const {
        return at(index);
    }
};

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

task4.cpp源代码:

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#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 << "测试1: 模板类接口测试\n";
    test1();

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

运行测试截图:

2.实验任务5

task5.cpp源码:

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

using std::string;
using std::ostream;
using std::istream;
using std::setw;
using std::setprecision;
using std::setiosflags;
using std::ios_base;

class Contestant {
public:
    Contestant() = default;
    ~Contestant() = default;
    int get_num() const { return num; }
    string get_major() const { return major; }
    friend ostream& operator<<(ostream& out, const Contestant& c);
    friend istream& operator>>(istream& in, Contestant& c);
private:
    string no; // 学号
    string name; // 姓名
    string major; // 专业
    int num; // 分数
};

// 友元函数实现
// 重载流插入运算符<<
ostream& operator<<(ostream& out, const Contestant& c) {
    out << setiosflags(ios_base::left);
    out << setw(10) << c.no
        << setw(10) << c.name
        << setw(10) << c.major
        << setw(5) << c.num;
    return out;
}

// 重载流提取运算符>>
istream& operator>>(istream& in, Contestant& c) {
    in >> c.no >> c.name >> c.major >> c.num;
    return in;
}

bool compare(const Contestant& c1, const Contestant& c2) {
    if (c1.get_major() > c2.get_major()) {
        return false;
    }
    if (c1.get_major() == c2.get_major())
        return c1.get_num() >c2.get_num();

    return true;
}

void output(std::ostream& out, const std::vector<Contestant>& v) {
    for (const auto& i : v)
        out << i << std::endl;
}

void save(const std::string& filename, const std::vector<Contestant>& v) {
    std::ofstream out(filename);
    if (!out.is_open()) {
        std::cout << "fail to open file to write\n";
        return;
    }
    output(out, v);
    out.close();
}

void load(const std::string& filename, std::vector<Contestant>& v) {
    std::ifstream in(filename);
    if (!in.is_open()) {
        std::cout << "fail to open file to read\n";
        return;
    }
    std::string title_line;
    getline(in, title_line); // 跳过标题行
    Contestant t;
    while (in >> t)
        v.push_back(t);
    in.close();
}

void test() {
    std::vector<Contestant> v;
    load("data5.txt", v); // 从文件加载选手信息到对象v
    std::sort(v.begin(), v.end(), compare); 
    output(std::cout, v); // 输出对象v中信息到屏幕
    save("ans5.txt", v); // 把对象v中选手信息保存到文件
}

int main() {
    test();
    return 0;
}

运行结果截图: