实验六

task3

task3_1.cpp

#include <iostream>
#include <fstream>
#include <array>
#define N 5

int main() {
    using namespace std;

    array<int, N> x {97, 98, 99, 100, 101};

    ofstream out;
    out.open("data1.dat", ios::binary);
    if(!out.is_open()) {
        cout << "fail to open data1.dat\n";
        return 1;
    }

    out.write(reinterpret_cast<char *>(&x), sizeof(x));
    out.close();
}

　　task3_2.cpp

#include <iostream>
#include <fstream>
#include <array>
#define N 5

int main() {
    using namespace std;
    array<char, N> x;

    ifstream in;
    in.open("data1.dat", ios::binary);
    if(!in.is_open()) {
        cout << "fail to open data1.dat\n";
        return 1;
    }

    in.read(reinterpret_cast<char *>(&x), sizeof(x));
    in.close();

    for(auto i = 0; i < N; ++i)
        cout << x[i] << ", ";
    cout << "\b\b \n";
}

task4

Vector.hpp

#pragma once

#include<iostream>
using std::cout;
using std::endl;

template<class T>
class Vector
{
    public:
        Vector(int n) :num{ n }, data{ new T[n] } {};
        Vector(int n, T x) :num{ n }, data{ new T[n] } 
        {
            for (int i = 0; i <n; ++i)
                data[i] = x;
        }
        Vector(const Vector& obj);
        ~Vector() { delete data; }
        
        int get_size()const { return num; }
        T& at(int i) { return data[i]; }
        T& operator[](int i) { return data[i]; }

        friend void output(Vector& obj)
        {
            for (int i=0;i<obj.num;++i)
                cout << obj.data[i]<<",";
            cout << "\b\b" << endl;
        }

    private:
        T* data;
        int num;
};

template<typename T>
Vector<T>::Vector(const Vector& obj) :num{obj.num}
{
    data = new T[obj.num];
    for (int i = 0; i <obj.num; ++i)
        data[i] = obj.data[i];
}

　　task4.cpp

#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();
}

 task5

task5.cpp

#include<iostream>
#include<fstream>
#include<iomanip>
using std::cout;
using std::endl;
using std::setw;

void output(std::ostream &out)
{
	out<<setw(4)<<" ";
	for(int i=0;i<26;++i)
		out<<setw(4)<<char('a'+i);
	out<<endl;
	for(int i=1;i<=26;++i)
	{
		out<<setw(4)<<i;
		for(int j=0;j<26;++j)
			out<<setw(4)<<char('A'+(i+j)%26);
		out<<endl;
	}
}
int main()
{
	output(cout);
	std::ofstream fout;
	fout.open("cipher_key.txt");
	output(fout);
	fout.close();
}