实验6 模板类、文件IO和异常处理

实验任务4

#pragma once

#include<iostream>
#include<stdexcept>

using namespace std;

template<typename T>
class Vector {
public:
    Vector(int n);
    Vector(int n, T value);
    Vector(const Vector<T> &vi);
    ~Vector();
    
    int get_size() const {return size;}
    T& at(int index);
    T& operator[](int index);
    
    template<typename T1>
    friend void output(const Vector<T1> &v);
    
private:
    int size;
    T *ptr;
};

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

template<typename T> 
Vector<T>::Vector(const Vector<T> &vi): size{vi.size}, ptr{new T[size]}
{
    for(auto i = 0; i < size; ++i)
      ptr[i] = vi.ptr[i]; 
}

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

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

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

template<typename T1>
void output(const Vector<T1> &v) {
    for(auto i = 0; i < v.get_size(); ++i)
       cout << v.ptr[i] << ", ";
    cout << "\b\b \n";
}

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

void test() {
    using namespace std;

    int n;
    cin >> n;
    
    Vector<double> x1(n);
    for(auto i = 0; i < n; ++i)
        x1.at(i) = i * 0.7;

    output(x1);

    Vector<int> x2(n, 42);
    Vector<int> x3(x2);

    output(x2);
    output(x3);

    x2.at(0) = 77;
    output(x2);

    x3[0] = 999;
    output(x3);
}

int main() {
    test();
}

实验任务5

#include <fstream>
#include <iomanip>

void output(std::ostream &out) {
    out << std::setw(4) << 'a';
    for (char i = 'b'; i <= 'z'; i++) {
        out << std::setw(2) << i;
    }
    out << std::endl;
    
    int n = 26;
    char start_letter = 'A';

    for (int i = 1; i <= n; i++) {
        out << std::setw(2) << i << " ";
        for (int j = 0; j < n; j++) {
            char letter = start_letter + (i + j) % n;
            out << letter << " ";
        }
        out << std::endl;
    }
}

int main() {
    output(std::cout);
    std::cout << std::endl;

    std::ofstream out;
    out.open("cipher_key.txt");
    if (!out.is_open()) {
       std::cout << "fail to open file " << "cipher_key.txt" << std::endl;
    } 
    output(out);
    out.close();
    return 0;
}