实验六

#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";
}

char类型一次只读取一个字节int 类型占四个字节，所以改为char后b会在第五个出现

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

    friend void output(Vector& obj1)
    {
        int i;
        for (i = 0; i < obj1.size-1; i++)
            cout << obj1.p[i] << " ";
        cout << endl;
    }
};



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)
{
   char a[26][26];
    cout << "  ";
    out << "  ";
    for (char i = 'a'; i <= 'z'; i++)
    {
        cout << setw(2) << setfill(' ') << i;
        out << setw(2) << setfill(' ') << i;
    }
    cout << endl;
    out << endl;
    for (int j = 0; j < 26; j++)
    {
        cout << setw(2) << setfill(' ') << j + 1;
        out << setw(2) << setfill(' ') << j + 1;
        for (int k = 0; k < 26; k++)
        {
            a[j][k] = 'A' + char((j + k + 1) % 26);
            cout << setw(2) << setfill(' ') << a[j][k];
            out << setw(2) << setfill(' ') << a[j][k];
        }
        out << endl;
        cout << 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();
}