task3
程序源码
task3_1.cpp
1 #define _CRT_SECURE_NO_WARNINGS 1
2 #include <iostream>
3 #include <fstream>
4 #include <array>
5 #define N 5
6 using namespace std;
7
8
9 int main() {
10 array<int, N> x{ 97, 98, 99, 100, 101 };
11 ofstream out;
12 out.open("data1.txt", ios::binary);
13 if (!out.is_open()) {
14 cout << "fail to open data" << endl;
15 return 1;
16 }
17 out.write(reinterpret_cast<char*>(&x), sizeof(x));
18 out.close();
19 }
task3_2.cpp
1 #define _CRT_SECURE_NO_WARNINGS 1
2 #include <iostream>
3 #include <fstream>
4 #include <array>
5 #define N 5
6 using namespace std;
7 int main() {
8 array<char, N> x;
9 ifstream in;
10 in.open("data1.txt", ios::binary);
11 if (!in.is_open()) {
12 cout << "fail to open data.dat\n";
13 return 1;
14 }
15 in.read(reinterpret_cast<char*>(&x), sizeof(x));
16 in.close();
17 for (auto i = 0; i < N; i++) {
18 cout << x[i] << ",";
19 }
20 cout << "\b\b\n";
21 return 0;
22 }
程序运行截图：
因为char是一个字节，而int为4个字节，char相对少了3个字节，空出来留给下一次读取。
task4
程序源码：
Vector.hpp
1 #pragma once
2 #include <iostream>
3 using namespace std;
4
5 template<class T>
6 class Vector {
7 public:
8 Vector(int size);
9 Vector(int size, T value);
10 ~Vector();
11 Vector(const Vector& x);
12 int get_size() const { return size; }
13 T& at(int index);
14 T& operator[](int index);
15 template<typename T>
16 friend void output(const Vector<T> &v);
17
18 private:
19 int size;
20 T* a;
21 };
22 template<typename T>
23 void output(const Vector<T>& v) {
24 for (int i = 0; i < v.size; i++) {
25 cout << v.a[i] << ",";
26 }
27 cout << "\b\b\n";
28 }
29 template<class T>
30 Vector<T>::Vector(int size) : size(size) {
31 a = new T[size];
32
33 }
34 template<typename T>
35 Vector<T>::Vector(int size, T value) : size(size) {
36 a = new T[size];
37 for (int i = 0; i < size; i++) {
38 a[i] = value;
39 }
40 }
41 template<typename T>
42 Vector<T>::~Vector() {
43 delete[] a;
44 }
45 template<typename T>
46 Vector<T>::Vector(const Vector& x) {
47 this->size = x.size;
48 this->a = new T[size];
49 for (int i = 0; i < size; i++) {
50 this->a[i] = x.a[i];
51 }
52 }
53
54 template<typename T>
55 T& Vector<T>::at(int index) {
56 return this->a[index];
57 }
58
59 template<typename T>
60 T& Vector<T>::operator[](int index) {
61 return this->a[index];
62 }
task4.cpp
1 #define _CRT_SECURE_NO_WARNINGS 1
2 #include <iostream>
3 #include "Vector.hpp"
4 using namespace std;
5
6 void test() {
7 int n;
8 cin >> n;
9 Vector<double> x1(n);
10 for (auto i = 0; i < n; i++) {
11 x1.at(i) = i * 0.7;
12 }
13 Vector<int> x2(n, 42);
14 Vector<int> x3(x2);
15 output(x2);
16 output(x3);
17 x2.at(0) = 77;
18 output(x2);
19 x3[0] = 999;
20 output(x3);
21
22 }
23
24 int main() {
25 test();
26 return 0;
27 }
程序运行截图：
task5
程序源码
1 #define _CRT_SECURE_NO_WARNINGS 1
2 #include <iostream>
3 #include <fstream>
4 #include <iomanip>
5 using namespace std;
6 void output(ostream& out) {
7 cout << " ";
8 for (int i = 97; i < 97 + 26; i++) {
9 cout << char(i) << " ";
10 }
11 cout << endl;
12 for (int i = 1; i <= 26; i++) {
13 cout << setw(2) << i ;
14 for (int j = 65 + i; j <= 65 + 25; j++) {
15 cout << char(j) << " ";
16 }
17 for (int k = 65; k < 65 + i; k++) {
18 cout << char(k) << " ";
19 }
20 cout << endl;
21 }
22
23
24
25 }
26 int main() {
27 ofstream ofs;
28 ofs.open("cipher_key.txt");
29 if (!ofs.is_open()) {
30 cout << "faile to open" << endl;
31 }
32 else {
33 ofs << setiosflags(ios::left) << setw(2) << "";
34 for (int i = 97; i < 97 + 26; i++) {
35 ofs << setiosflags(ios::left) <<setw(2) << char(i) << " ";
36 }
37 ofs << endl;
38 for (int i = 1; i <= 26; i++) {
39 ofs << setiosflags(ios::left) << setw(2) << i;
40 for (int j = 65 + i; j <= 65 + 25; j++) {
41 ofs << setiosflags(ios::left) << setw(2) <<char(j) << " ";
42 }
43 for (int k = 65; k < 65 + i; k++) {
44 ofs << setiosflags(ios::left) << setw(2) << char(k) << " ";
45 }
46 ofs << endl;
47 }
48
49 }
50 ofs.close();
51 output(ofs);
52 return 0;
53 }
运行截图
这里在txt文件一直大小写字母对不齐，于是我换了一个字体就成功了
标签：int,Vector,实验,oop,template,output,include,模板,size From： https://www.cnblogs.com/abcdefg-gaoyuan/p/16943037.html