实验6 模板类、文件I/O和异常处理

实验任务4：

vector.hpp

 

#pragma once

#include<iostream>
#include<stdexcept>
#include<string>

using namespace std;

template<typename T>
class Vector
{
public:
    Vector(int s);
    Vector(int s, T value);
    Vector(const Vector<T>& v);
    ~Vector();


    T get_size()const;
    T& at(int index);
    T& at(int index)const;
    T& operator[](int index);
    T& operator[](int index)const;

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


private:
    int size;
    T* ptr;
};

template<typename T>
Vector<T>::Vector(int s):size{s}
{
    if (s < 0) { throw length_error("Vector constructor: negative size."); }
    ptr = new T[size];
}

template<typename T>
Vector<T>::Vector(int s, T value) :size{ s }
{
    if (s < 0) { throw length_error("Vector constructor: negative size."); }
    ptr = new T[size];
    for (int i = 0; i < size; i++)
    {
        ptr[i] = value;
    }
}

template<typename T>
Vector<T>::Vector(const Vector<T>& v):size(v.size)
{
    ptr = new T[size];
    for (int i = 0; i < size; i++)
    {
        ptr[i] = v.ptr[i];
    }
}

template<typename T>
Vector<T>::~Vector()
{
    delete[] ptr;
}

template<typename T>
T Vector<T>::get_size()const
{
    return size;
}

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

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

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


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

template<typename U>
void output(const Vector<U>& v)
{
    for (int i = 0; i < v.get_size(); i++)
    {
        cout << v[i] << " ";
    }
    cout << endl;
}

 

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() {
    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();
}

运行结果截图：

 

 

 

 

实验任务5：

task5.cpp

 

#include"Student.h"
#include<iostream>
#include<fstream>
#include<vector>
#include<algorithm>

using namespace std;

bool compare(const students& s1, const students& s2)
{
    if (s1.get_maj() < s2.get_maj()) { return true; }
    if (s1.get_maj() == s2.get_maj())
    {
        return s1.get_score() > s2.get_score();
    }
}

void output(ostream& out, const vector<students>& S)
{
    for (auto &i : S)
    {
        out << i;
    }
}

int main()
{
    vector<students> S;
    ifstream fin("data5.txt");
    if (!fin.is_open()) { cout << "fail to open data5.txt"; return -1; }
    string line;
    getline(fin, line);     //输入提示
    students s;
    while (fin >> s)
    {
        S.push_back(s);
    }
    sort(S.begin(), S.end(), compare);
    ofstream fout("ans5.txt");
    if (!fout.is_open()) { cout << "fail to open ans5.txt"; return -1; }
    output(cout, S);
    output(fout, S);
    return 0;
}

 

 

 

 

运行结果截图：

原始数据：

 

 

 

 

 

 

 

ans5.txt