实验6 模板类和文件I/O

实验任务3

task3_1

 1 #include<iostream>
 2 #include<fstream>
 3 #include<array>
 4 #define N 5
 5 
 6 int main() {
 7     using namespace std;
 8     array<int, N> x{ 97,98,99,100,101 };
 9 
10     ofstream out;
11     out.open("data1.dat", ios::binary);
12     if (!out.is_open()) {
13         cout << "fail to open data1.dat\n";
14         return 1;
15     }
16 
17     //把从地址&x开始连续sizeof(x)个字节数据块写入文件data1.txt
18     out.write(reinterpret_cast<char*>(&x), sizeof(x));
19     out.close();
20 }

task3_2

 1 #include<iostream>
 2 #include<fstream>
 3 #include<array>
 4 #define N 5
 5 int main() {
 6     using namespace std;
 7     array<int, N> x;
 8     ifstream in;
 9     in.open("data1.dat", ios::binary);
10     if (!in.is_open()) {
11         cout << "fail to open data1.dat\n";
12         return 1;
13     }
14     in.read(reinterpret_cast<char* >(&x), sizeof(x));
15     in.close();
16     for (auto i = 0; i < N; i++)
17         cout << x[i] << ", ";
18     cout << "\b\b \n";
19 }

运行测试截图：

将array<int,N> x;修改成array<char,N> x;运行结果为：

实验任务4

Vector.hpp

 1 #pragma once
 2 #include<iostream>
 3 
 4 using namespace std;
 5 
 6 template<typename T>
 7 class Vector {
 8 public:
 9     Vector(int n) :size{ n } { p = new T[n]; }
10     Vector(int n, T value);
11     Vector(const Vector<T>& v);
12     ~Vector() { delete p; }
13     T get_size() { return size; }
14     T& at(int index) const {return p[index]; }
15     T& operator[](int i)const { return p[i]; }
16     template<typename T1>
17     friend void output(const Vector<T1>& v);
18 private:
19     T* p;
20     int size;
21 };
22 template<typename T>
23 Vector<T>::Vector(int n, T value):size(n) {
24     p = new T[n];
25     for (auto i = 0; i < n; i++)
26         p[i] = value;
27 }
28 template<typename T>
29 Vector<T>::Vector(const Vector<T>& v):size(v.size) {
30     p = new T[size];
31     for (auto i = 0; i < size; i++) {
32         p[i] = v.p[i];
33     }
34 }
35 template<typename T1>
36 void output(const Vector<T1>& v) {
37     for (auto i = 0; i < v.size; i++)
38         cout << v.p[i] << ", ";
39     cout << "\b\b \n";
40 }

task4.cpp

 1 #include <iostream>
 2 #include "Vector.hpp"
 3 void test() {
 4     using namespace std;
 5     int n;
 6     cin >> n;
 7     Vector<double> x1(n);
 8     for (auto i = 0; i < n; ++i)
 9         x1.at(i) = i * 0.7;
10     output(x1);
11     Vector<int> x2(n, 42);
12     Vector<int> x3(x2);
13     output(x2);
14     output(x3);
15     x2.at(0) = 77;
16     output(x2);
17     x3[0] = 999;
18     output(x3);
19 }
20 int main() {
21     test();
22 }

运行测试结果：

改变测试数据，运行结果：

实验任务5

task5.cpp

 1 #include<iostream>
 2 #include<fstream>
 3 #include<iomanip>
 4 #include<string>
 5 
 6 using namespace std;
 7 
 8 void output(ostream& out) {
 9 
10     string a[27][27]= {" "};
11 
12     for (int i = 1; i < 27; i++) {
13         a[0][i] = 96 + i;
14         a[i][0] = to_string(i);
15     }
16     int k = 1;
17     for (int i = 1; i < 27; i++) {
18 
19         for (int j = 1; j < 27; j++) {
20             a[i][j] = 65 + ((65 + k) % 65) % 26;
21             k++;
22         }
23         k = i + 1;
24     }
25     for (int i = 0; i < 27; i++) {
26         for (int j = 0; j < 27; j++) {
27             cout << right << setw(2) << a[i][j];
28             out << right << setw(2) << a[i][j];
29         }
30         cout << endl;
31         out << endl;
32     }
33 }
34 int main() {
35     ofstream outfile;
36     outfile.open("cipher_key.txt");
37     if (!outfile.is_open()) {
38         cout << "fail to open cipher_key.txt\n";
39         return 0;
40     }
41     output(outfile);
42     outfile.close();
43 }

运行测试结果：