实验六

#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();
}

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

int main() {
    using namespace std;
    array<int, 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";
}

 

 将array的参数改为char：

 

 原因：当int类型写入是，每个数据占四个字节，以char类型输出时每个数据占一个字节，产生空格。

#pragma once
#include<iostream>
using namespace std;
template<typename T>
class Vector {
public:
    Vector(int n) :size(n) {
        p = new T[size];
    }
    Vector(int n, T value) :size(n) {
        p = new T[size];
        for (int i = 0; i < size; i++)
            p[i] = value;
    }
    Vector(const Vector<T>& x):size(x.size) {
        p = new T[size];
        for(int i=0;i<size;i++)
            p[i]=x.p[i];
    }
    ~Vector() {
        delete[]p;
    }
    int get_size() {
        return size;
    }
    T& at(int i) {
        return p[i];
    }
    T& operator[](int i) {
        return p[i];
    }
    friend void output(const Vector<T>& x) {
        for (int i = 0; i < x.size; i++)
            cout << x.p[i] << ",";
        cout << endl;
    }
private:
    T* p;
    int size;
};

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

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();
}

 

 

 

 

#include<iostream>
#include<iomanip>
#include<string>
#include<fstream>
using namespace std;
void output(std::ostream& out)
{
    int row = 1;
    char a[26][26];
    cout << " ";
    out << "  ";
    for (char i = 'a'; i <= 'z'; i++) {
        cout << i << " ";
        out << i << " ";
    }
    cout << endl;
    out << endl;
    for (int i = 0; i < 26; i++) {
        cout << i + 1 << " ";
        out << i + 1 << " ";
        for (int j = 0; j < 26; j++) {
            a[i][j] = 'A' + char((i + j + 1) % 26);
            cout << a[i][j] << " ";
            out << a[i][j] << " ";
        }
        cout << endl;
        out << endl;
    }
}
int main()
{
    ofstream out;
    out.open("cipher_key.txt", ios::out);
    if (!out.is_open())
    {
        cout << "fail to open cipher_ke.text" << endl;
        return 1;
    }
    output(out);
    out.close();
}