实验6

task4

#pragma once

#include<iostream>
#include<stdexcept>

using namespace std;
template<typename T>
class Vector {
public:
    Vector(int size = 0, T value = T()) :m_size(size) {
        if (size < 0) {
            throw std::length_error("Vector constructor:negative size");
        }
        m_data = new T[size];
        for (int i = 0;i < size;++i) {
            m_data[i] = value;
        }
    }

    Vector(const Vector<T>& other) :m_size(other.m_size) {
        m_data = new T[m_size];
        for (int i = 0;i < m_size;++i) {
            m_data[i] = other.m_data[i];
        }
    }
    ~Vector() {
        delete[]m_data;
    }

    int get_size()const {
        return m_size;
    }

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

    T& operator[](int index) {
        if(index<0||index>=m_size){
            throw std::out_of_range("Vector:index out of range");
        }
        return m_data[index];
    }

    friend std::ostream& operator<<(std::ostream& os, const Vector<T>& v) {
        for (int i = 0;i < v.m_size;++i) {
            os << v.m_data[i];
            if (i < v.m_size - 1) {
                os << ",";
            }
        }
        return os;
    }
    
    friend void output(const Vector<T>& v) {
    std::cout << v << std::endl;
}

private:
    T* m_data;
    int m_size;
};

#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();
}

task5

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

using namespace std;

class Grade{
    public:
        Grade(const string &n,const string &na,const string &ma,int score);
        ~Grade()=default;
        
        int get_score() const{return score;}
        string get_major() const{return major;}
        string get_no()const{return no;}
        string get_name()const{return name;}
    private:
        string no;
        string name;
        string major;
        int score;
};

Grade::Grade(const string &n,const string &na,const string &ma,int score):no{n},name{na},major{ma},score{score}{}

bool compare_Grade(const Grade& a,const Grade& b){
    if(a.get_major()<b.get_major())return true;
    if(a.get_major()>b.get_major())return false;
    return a.get_score()>b.get_score();
}
 
int main(){
    vector<Grade>grades;
    ifstream in("data5.txt");
    if(in.is_open()){
        string line;
        getline(in,line);
         
        string no,name,major;
        int score;
        while(in>>no>>name>>major>>score){
            grades.push_back(Grade(no,name,major,score));
        }
        in.close();
    }else{
        cout<<"fail to open file to read\n";
        return 1; 
    }
    
    sort(grades.begin(),grades.end(),compare_Grade);
    
    ofstream out("ans5.txt");
    if(out.is_open()){
        for(const Grade&g:grades){
            out<<g.get_no()<<" "<<g.get_name()<<" "<<g.get_major()<<" "<<g.get_score()<<endl;
            cout<<g.get_no()<<" "<<g.get_name()<<" "<<g.get_major()<<" "<<g.get_score()<<endl;
        }
    }else{
        cout<<"fail to open file to write\n";
        return 1;
    }
    return 0;
}