实验六c++

实验任务四

源代码

Vector.hpp

#include<iostream>
#include<stdexcept>
using namespace std;

template<typename T>
class Vector {
public:
    Vector(int n);
    Vector(int n, T a);
    Vector(const Vector<T>& c);
    ~Vector();

    int get_size()const { return n; }
    T& at(int i);
    T operator[](int i)const;

    template<typename T>
    friend void output(Vector<T> t);
private:
    T* ptr;
    int n;
};
template<typename T>
Vector<T>::Vector(int n):n(n) {
    if (n < 0)
        throw length_error("Vector constructor: negative size");
    else
        ptr = new T[n];
}

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

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

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

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

template<typename T>
void output(Vector<T> t) {
    for (int i = 0; i < t.n;i++) {
        cout << t.ptr[i] << ", ";
    }
    cout <<"\b\b "<< endl;
}

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();
}

运行结果截图

实验任务五

源代码

data5.hpp

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

using namespace std;

class Student {
public:
    Student() = default;
    ~Student() = default;
    string getcourse()const { return course; }
    int getso()const { return score; }

    friend ostream& operator<<(ostream& out, const Student& s);
    friend istream& operator>>(istream& in, Student& s);
private:
    int num;
    string name;
    string course;
    int score;

};

ostream& operator<<(ostream& out, const Student& s) {
    out << left;
    out << setw(15) << s.num
        << setw(15) << s.name
        << setw(15) << s.course
        << setw(15) << s.score;
    return out;
}
istream& operator>>(istream& in, Student& s) {
    in >> s.num >> s.name >> s.course >> s.score;
    return in;
}

sort.cpp

#include<iostream>
#include<algorithm>
#include<fstream>
#include<string>
#include"data5.hpp"
#include<vector>

using namespace std;
bool compare_by_so(const Student& s1, const Student& s2) {
    if (s1.getcourse() > s2.getcourse())
        return true;
    if (s1.getcourse() == s2.getcourse())
        return s1.getso() > s2.getso();

    return false;
}

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

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

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

void load(const string& filename, vector<Student>& v) {
    ifstream in(filename);
    if (!in.is_open()) {
        cout << "fail to open file to write\n";
        return;
    }

    string title;
    getline(in, title);

    Student s;
    while (in >> s)
        v.push_back(s);
    in.close();
}
void test() {
    using namespace std;

    vector<Student> v;

    load("data5.txt", v);
    sort(v.begin(), v.end(), compare_by_so);
    output(cout, v);
    save("ans5.txt", v);
}

int main() {
    test();
}

运行结果截图