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";
}

将代码中的array<int,N> x 改为array<char,N> x 后，运行结果为：

将int改为char后，输入a b c d e，会将空格也读进去，又因为int类型的数据占四个字符，对编译器来说输入的其实是a，空格，空格，空格，b

所以输出结果才会改变。

#include <iostream>
using namespace std;
template<typename T>

class Vector
{
    public:
        Vector(int n):size{n} {p = new T[n];}
        
        Vector(int n,T value):size{n}{
            p = new T[n];
            for(auto i=0;i<size;i++)
            p[i]=value;
        }
        
        Vector(const Vector<T>&a):size{a.size}{
            p=new T[size];
            for(auto i=0;i<size;i++)
            p[i]=a.p[i];
        }
        
        template<typename T1>
        friend void output(const Vector<T1>&a);
        
        T get_size()const{
            return size;
        }
            
        T& at(int index){
            return p[index];
        }
        
        T& operator[](int i){
            return p[i];
        }
                
    private:
        int size;
        T *p;    
};

template<typename T1>
void output(const Vector<T1>&a){
    for(auto i=0;i<a.size;i++)
        cout<<a.p[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();
}

#include<iostream>
#include<iomanip>
#include<fstream>
using namespace std;
char password[30][30];

void output(std::ostream &out);

int main(){
    ofstream out;
    
    password[0][0]=' ';
    for(int i=0,j=1;j<=26;j++)
        password[i][j]='a'+j-1;
    for(int i=1,j=0;i<=26;i++)
        password[i][j]=i+'0';
    for(int i=1;i<=26;i++){
        for(int j=1;i+j<=26;j++)
            password[i][j]='A'+i+j-1;
    }
    for(int i=26;i>=1;i--)
        for(int j=26;i+j>26&&j>=1;j--)
            password[i][j]='A'+i+j-27;
    out.open("cipher_key.txt", ios::binary);
    if(!out.is_open()) {
        cout << "fail to open cipher_key.txt\n";
        return 1;
    }
    output(out);
    system("pause");
}

void output(std::ostream &out){
    for(int i=0;i<=26;i++){
        for(int j=0;j<=26;j++){
            if(j==0&&i!=0)
                cout<<left<<setw(2)<<password[i][j]-'0'<<" ";
            else
                cout<<left<<setw(2)<<password[i][j]<<" ";
        }
            cout<<endl;
    }
    for(int i=0;i<=26;i++){
        for(int j=0;j<=26;j++){
            if(j==0&&i!=0)
                out<<left<<setw(4)<<password[i][j]-'0'<<" ";
            else
                out<<left<<setw(4)<<password[i][j]<<"  ";
        }
            out<<endl;
    }
}