实验6 模板类、文件I/O和异常处理

实验任务4：

实验代码：

#pragma once
#include<iostream>
#include<stdexcept>
using namespace std;
template<typename T>
class Vector{
    public:
        Vector(int n,const T& value=T()):size(n){
            if(n<0)
            {
                throw length_error("Vector constructor:negative size!");
            }
            else
            {
                x=new T[n];
                for(int i=0;i<n;i++)
                {
                    x[i]=value;
                }
            }
        }
        Vector(const Vector<T>& other):size(other.size){
            x=new T[size];
            for(int i=0;i<size;i++)
            {
                x[i]=other.x[i];
            }
        }
        ~Vector(){
            delete[] x;
         }
         
         
         int get_size() const{
             return size;
        }
        
        
        T& at(int index){
                if(index>=size)
            {
                throw out_of_range("Vector:index out of range!");
            }
            else
            return x[index];
        }
        const T& at(int index) const
        {
            if(index>=size)
            {
                throw out_of_range("Vector:index out of range!");
            }
            else
            return x[index];
        }
        
        
        T& operator[](int i){
            return at(i);
        }
        const T& operator[](int i)const{
            return at(i);
        }
        
        
        friend void output(const Vector<T>& a)
        {
            int i;
            for( i=0;i<a.size-1;i++)
            {
                cout<<a[i]<<", ";
            }
            cout<<a[i];
            cout<<endl; 
        }
    private:
        int size;
        T* x;
};

#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() {
    using namespace std;
    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：

实验代码：

 

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


struct Student {
    std::string id;
    std::string name;
    std::string major;
    int score;
};


bool compareStudents(const Student& s1, const Student& s2) {
    if (s1.major < s2.major) {
        return true;
    }
    else if (s1.major == s2.major) {
        return s1.score > s2.score;
    }
    return false;
}

int main() {
    std::vector<Student> students;
    std::ifstream in("data5.txt");
   

    std::string line;
    
    std::getline(in, line);

    while (std::getline(in, line)) {
        std::istringstream iss(line);
        Student student;
        iss >> student.id >> student.name >> student.major >> student.score;
        students.push_back(student);
    }

    in.close();

    std::sort(students.begin(), students.end(), compareStudents);

    std::ofstream out("ans5.txt");
    
    for (const auto& student : students) {
        std::cout << student.id << " " << student.name << " " << student.major << " " << student.score << std::endl;
        out << student.id << " " << student.name << " " << student.major << " " << student.score << std::endl;
    }

    out.close();

    return 0;
}

 

运行结果截图：