实验6

实验六

实验任务4

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) { // 多组输入，按
下Ctrl+Z终止
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();
}

vector.hpp

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

template<typename T>
class Vector
{
private:
    int size;
    T* ptr;
public:
    Vector(int n);
    Vector(int n, T value);
    Vector(const Vector<T>& v);
    ~Vector();

    int get_size()
    {
        return size;
    }

    T& at(int index)const;
    T& at(int index);

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

    template<typename T1>                             
    friend void output(const Vector<T1>& v);
};

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


template<typename T>
Vector<T>::Vector(int n,T value):size(n)
{

    if (n < 0)
    {
        throw length_error("Vector constructor:negative size");
    }
    else
    {
        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>::at(int index)const
{
    if (index < 0 || index >= size)
    {
        throw out_of_range("Vector:index out of range");
    }
    else
    {
        return ptr[index];
    }

}

template<typename T>
T& Vector<T>::at(int index)
{
    return static_cast<const Vector*>(this)->at(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");
    }
    else
    {
        return ptr[index];
    }

}
template<typename T>
T& Vector<T>::operator[](int index)
{
    return static_cast<const Vector*>(this)->operator[](index);

}

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

}

实验任务5

task5.cpp

#include <fstream>
#include <iostream>
#include <string>
#include<vector>
using namespace std;

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

int main() {
  auto fin = ifstream("data5.txt");
  if (!fin) {
    cout << "Failed to open file." << endl;
    return 1;
  }
  string line;
  getline(fin, line);
  auto stus = vector<Student>();
  while (!fin.eof()) {
    int id, score;
    string name, major;
    fin >> id >> name >> major >> score;
    stus.push_back({id, name, major, score});
  }
  auto fout = ofstream("ans5.txt");
  for (auto &stu : stus) {
    cout << stu.id << " " << stu.name << " " << stu.major << " " << stu.score
         << endl;
    fout << stu.id << " " << stu.name << " " << stu.major << " " << stu.score
         << endl;
  }
  return 0;
}