实验6 模板类、文件I/O和异常处理

实验任务1-3：

验证性实验。无需写入实验博客文档。 

已亲自动手实践。

实验任务4：

#pragma once
#include<iostream>
#include<stdexcept>
using namespace std;
template <typename T>
class Vector{
    private:
        int size;
        T *data;
        template<typename T1>
      friend void output(const Vector<T1> &v) ;
        
    public:
    Vector(int n){
        if(n<0)
         throw length_error("Vector constructor:negative size");
        data =new T[n];
        size=n;
    }
    Vector(int n,T value){
        if(n<0)
         throw length_error("Vector constructor:negative size");
        data =new T[n];
        size=n;
        for(int i=0;i<n;i++)
        data[i]=value;
    }
     Vector(const Vector<T>& other) {
        size = other.size;
        data = new T[size];
        for (int i = 0; i < size; i++) {
            data[i] = other.data[i];
        }
    }
     ~Vector() {
        delete[] data;
    }
    int get_size()const{
         return size;     };
    T& at(int i) const {
         if(i<0||i>=size)throw out_of_range("Vector:index out of range");
         return data[i];
     };
    T& operator[](int i){
        if(i>size)throw out_of_range("Vector:index out of range");
        return data[i];
        
    }
    
};

template<typename T1>
void output(const Vector<T1> &v) 
{
    for(int i=0;i<v.size;i++){
    cout<<v.at(i)<<", ";
    }
    cout<<"\b\b "<<endl;
}

#include <iostream>
#include "Vector.hpp"

using namespace std;

void test1() {
    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();
}

实验任务5：

#pragma once
#include<iostream>
#include<iomanip>
#include<string>
#include<vector>
#include<fstream> 
 using namespace std;
 
 class Count{
     private:
     string id;
     string name;
     string major;
     int score;
     public:
         Count()=default;
         ~Count()=default;
         int get_score()const;
         string get_major()const;
         friend ostream& operator<<(ostream &out,const Count &c);
         friend istream& operator>>(istream &in,Count &c);
         
     
 };
 int Count::get_score()const{
 return score;
 }
 string Count::get_major() const{
 return major;
 }
 ostream& operator<<(ostream &out,const Count &c)
 {
     out << setiosflags(ios_base::left);
     out<<setw(15)<<c.id
        <<setw(15)<<c.name
        <<setw(15)<<c.major
        <<setw(5)<<c.score;
    return out;
    
 }
 istream& operator>>(istream &in, Count &c)
 {
     in>>c.id>>c.name>>c.major>>c.score;
     return in;
     
 }

#pragma once
#include "Student.hpp"
#include <vector>
#include<iostream>
#include<fstream>
#include <algorithm>

bool compare_by_major(const Count &c1,const Count &c2){
    if(c1.get_major() < c2.get_major())return true;
     if(c1.get_major() == c2.get_major())
         return c1.get_score()>c2.get_score();
     return false;
 }
 void output(ostream &out,const vector<Count> &v){
 for(auto &i: v)
        out << i << endl;
 }
 void load(const string &filename,vector<Count> &v){
  ifstream in(filename);
   if(!in.is_open()){
        cout << "fail to open file to read\n";
        return ;
    }
    string title_line;
    getline(in,title_line);
   Count c;
    while(in>>c)
        v.push_back(c);
    in.close();
}
void save(const string &filename,vector<Count> &v){
    ofstream out(filename);
    if(!out.is_open()){
        cout << "fail to open fele to write\n";
         return ;
     }
    output(out,v);
    out.close(); 
}

#include "Student.hpp"
#include"utils.hpp"
#include<iostream>
#include<vector>
#include<algorithm>

int main(){
    vector<Count> v;
    load("data5.txt",v);
    sort(v.begin(),v.end(),compare_by_major);
    output(cout,v);
    save("ans5.txt",v);
    return 0;
}