实验6 模版类、文件I/O和异常处理

任务4：

Vector.hpp:

#pragma once
#include <iostream>
using namespace std;

template <typename T>
class Vector {
private:
    int size_;
    T* data_;

public:

    Vector(int n);

    Vector(int n, T value);

    Vector(const Vector<T>& v) : size_(v.size_), data_(new T[v.size_]) {
        for (int i = 0; i < size_; ++i) {
            data_[i] = v.data_[i];
        }
    }

    ~Vector() {}

    int size() const { return size_; }

    T& at(int index) {
        if (index < 0 || index >= size_) {
            throw out_of_range("Vector: Index out of range");
        }
        return data_[index];
    }

    const T& at(int index) const {
        if (index < 0 || index >= size_) {
            throw out_of_range("Vector: Index out of range");
        }
        return data_[index];
    }

    T& operator[](int index) { return data_[index]; }
    const T& operator[](int index) const { return data_[index]; }

    template <typename T1>
    friend void output(const Vector<T1>& v);
};


template <typename T>
void output(const Vector<T>& v) {
    for (int i = 0; i < v.size_; ++i) {
        cout << v.data_[i];
        if (i != v.size_ - 1) cout << ", ";
    }
    cout << endl;
}
template<typename T>
Vector<T>::Vector(int n) : size_(n){
        if (n < 0) {
            throw length_error("Vector constructor: negative size");
        }
        else
        {
            data_ = new T[size_];
        }
    }
template<typename T>
Vector<T>::Vector(int n, T value) : size_(n) {
        if (n < 0) {
            throw length_error("Vector constructor: negative size");
        }
        else
        {
            data_ = new T[size_];
            for (int i = 0; i < size_; i++)
            {
                data_[i] = value;

            }
        }
    }

task.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() {
    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();
}

 

 

任务5：

people.hpp:

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

using namespace std;

class people
{
private:
    int xuehao;
    string name;
    string major;
    int score;
public:
    people() = default;
    ~people() = default;

    string get_major()const
    {
        return major;
    }
    int get_score()const
    {
        return score;
    }

    friend ostream& operator<<(ostream& out, people& p);
    friend istream& operator>>(istream& in, people& p);


};

ostream& operator<<(ostream& out, people& p)
{
    out << setiosflags(ios_base::left);
    out << setw(10) << p.xuehao
        << setw(10) << p.name
        << setw(10) << p.major
        << setw(10) << p.score << endl;
    return out;

}

istream& operator>>(istream& in, people& p)
{
    in >> p.xuehao >> p.name >> p.major >> p.score;
    return in;



}

tools.hpp:

#pragma once
#include"people.hpp"
#include<iostream>
#include<string>
#include<fstream>
#include<vector>

bool paixu(const people& p1, const people& p2)
{
    if (p1.get_major() < p2.get_major())
    {
        return true;
    }
    if (p1.get_major() == p2.get_major())
    {
        return p1.get_score() > p2.get_score();

    }
    return false;

}

void output(ostream& out, vector<people>& v)
{
    for (auto& i : v)
    {
        out << i;
    }

}

void save(const string& filename, vector<people>& v)
{
    ofstream out(filename);
    if (!out.is_open())
    {
        cout << "文件写入失败" << endl;
        exit(0);
    }

    output(out, v);
    out.close();

}

void load(const string& filename, vector<people>& v)
{
    ifstream in(filename);

    if (!in.is_open())
    {
        cout << "文件读出失败" << endl;
        exit(0);
    }

    string firstline;
    getline(in, firstline);
    people p;
    while (in >> p)
    {
        v.push_back(p);
    }

    in.close();
}

task5.cpp:

#include"people.hpp"
#include"tools.hpp"
#include<iostream>
#include<string>
#include<vector>
#include<algorithm>

int main()
{

    vector<people> v;
    load("data5.txt", v);
    sort(v.begin(), v.end(), paixu);

    output(cout, v);
    save("ans.txt", v);


    return 0;
}

 总结：通过本次实验我体验到异常处理的基础用法，异常处理的机制和流程
；也训练了综合应用类的封装、继承、多态特性及现代C++标准库编写正确、高效、安全代码