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实验3 类与数组、指针

任务1：

 1 #pragma once
 2 
 3 #include <iostream>
 4 using std::cout;
 5 using std::endl;
 6 
 7 class Point {
 8 public:
 9     Point(int x0 = 0, int y0 = 0);
10     ~Point() = default;
11 
12     int get_x() const;
13     int get_y() const;
14     void show() const;
15     void move(int new_x, int new_y);
16 
17 private:
18     int x, y;
19 };
20 
21 Point::Point(int x0, int y0): x{x0}, y{y0} {   
22 }
23 
24 int Point::get_x() const {
25     return x;
26 }
27 
28 int Point::get_y() const {
29     return y;
30 }
31 
32 void Point::show() const {
33     cout << "(" << x << ", " << y << ")" << endl;
34 }
35 
36 void Point::move(int new_x, int new_y) {
37     x = new_x;
38     y = new_y;
39 }
Point.hpp源码
 1 #include <iostream>
 2 #include "point.hpp"
 3 #include <vector>
 4 
 5 using std::vector;
 6 using std::cin;
 7 
 8 // 输出vector<Point>对象内所有点的坐标
 9 void output(const vector<Point> &v) {
10     for(auto &t: v)
11         t.show();
12 }
13 
14 void test() {
15     int n;
16     cout << "输入动态Point数组类对象中元素个数: ";
17     cin >> n;
18 
19     vector<Point> x(n);
20     cout << "x对象中所有点坐标信息: " << endl;
21     output(x); 
22 
23     vector<Point> y(x);  // 基于vector<Point>对象x构建对象y
24     cout << "\nx对象中所有点坐标信息: " << endl;
25     output(y);
26     
27     cout << "\n更新x对象......" << endl;
28     x.at(0).move(30, 50);       // 更新对象x内索引为0的点对象坐标
29     x.push_back(Point(2, 2));   // 向x对象末尾添加一个点对象
30 
31     cout << "\nx对象中所有点坐标信息: " << endl;
32     output(x);          
33     cout << "\ny对象中所有点坐标信息: " << endl; 
34     output(y);           
35 }
36 
37 int main() {
38     test();
39 }
task1.cpp源码
运行结果截图：

问题一：不变化

问题二：深复制

任务2：

 1 #pragma once
 2 
 3 #include <iostream>
 4 using std::cout;
 5 using std::endl;
 6 
 7 class Point {
 8 public:
 9     Point(int x0 = 0, int y0 = 0);
10     ~Point() = default;
11 
12     int get_x() const;
13     int get_y() const;
14     void show() const;
15     void move(int new_x, int new_y);
16 
17 private:
18     int x, y;
19 };
20 
21 Point::Point(int x0, int y0): x{x0}, y{y0} {   
22 }
23 
24 int Point::get_x() const {
25     return x;
26 }
27 
28 int Point::get_y() const {
29     return y;
30 }
31 
32 void Point::show() const {
33     cout << "(" << x << ", " << y << ")" << endl;
34 }
35 
36 void Point::move(int new_x, int new_y) {
37     x = new_x;
38     y = new_y;
39 }
point.hpp
 1 #pragma once
 2 
 3 #include "point.hpp"
 4 #include <cassert>
 5 #include <iostream>
 6 
 7 class vectorPoint{
 8 public:
 9     vectorPoint(int n);
10     ~vectorPoint();
11     
12     int get_size() const;           // 获得当前动态数组内元素个数
13     Point& at(int index);           // 返回下标为index的元素引用
14     Point& at(int index) const;     // 返回下标为index的元素const引用
15 
16 private:
17     int size; // 动态数组的大小
18     Point *ptr;
19 };
20 
21 vectorPoint::vectorPoint(int n) : size{n} {
22     ptr = new Point[n];
23 }
24 
25 vectorPoint::~vectorPoint() {
26     delete[] ptr;
27 }
28 
29 int vectorPoint::get_size() const {
30     return size;
31 }
32 
33 Point& vectorPoint::at(int index) {
34     assert(index >= 0 && index < size);  // 宏，在测试模式下工作。如果不满足条件，则程序终止
35     return ptr[index];
36 }
37 
38 Point& vectorPoint::at(int index) const {
39     assert(index >= 0 && index < size);  
40     return ptr[index];
41 }
vectorPoint.hpp源码
 1 #include "vectorPoint.hpp"
 2 #include <iostream>
 3 
 4 // 输出vectorPoint对象内的所有数据
 5 void output(const vectorPoint &v) {
 6     for(auto i = 0; i < v.get_size(); ++i)
 7         v.at(i).show();
 8 }
 9 
10 // 测试vectorPoint类：构造对象、复制构造对象
11 void test() {
12     using namespace std;
13 
14     int n;
15     cout << "输入vectorPoint对象中元素个数: ";
16     cin >> n;
17 
18     vectorPoint x(n);
19     cout << "x对象中所有点坐标信息: " << endl;
20     output(x); 
21 
22     vectorPoint y(x);
23     cout << "\ny对象中所有点坐标信息: " << endl;
24     output(y); 
25 
26     cout << "\n更新x对象中点坐标信息......" << endl;
27     x.at(0).move(30, 50);
28     x.at(1).move(-1, -1);
29 
30     cout << "x对象中所有点坐标信息: " << endl;
31     output(x); 
32 
33     cout << "\ny对象中所有点坐标信息: " << endl;
34     output(y); 
35 }
36 
37 int main() {
38     test();
39 }
task2.cpp源码

运行结果截图：

问题一：发生变化

问题二：浅复刻

问题三：浅复刻

 任务3：

 1 #include "vectorPoint.hpp"
 2 #include <iostream>
 3 void output(const vectorPoint &v) {
 4 for(auto i = 0; i < v.get_size(); ++i)
 5 v.at(i).show();
 6 }
 7 void test() {
 8 using namespace std;
 9 int n;
10 cout << "input vectorPoint how much number: ";
11 cin >> n;
12 vectorPoint x(n);
13 cout << "x information: " << endl;
14 output(x);
15 vectorPoint y(x);
16 cout << "\ny information: " << endl;
17 output(y);
18 cout << "\nupdate x information......" << endl;
19 x.at(0).move(30, 50);
20 x.at(1).move(-1, -1);
21 cout << "x information: " << endl;
22 output(x);
23 cout << "\ny information: " << endl;
24 output(y);
25 }
26 int main() {
27 test();
28 }
task3.cpp
 1 #pragma once
 2 #include "point.hpp"
 3 #include <cassert>
 4 #include <iostream>
 5 class vectorPoint{
 6 public:
 7 vectorPoint(int n);
 8 vectorPoint(const vectorPoint &vp);
 9 ~vectorPoint();
10 int get_size() const;
11 Point& at(int index);
12 Point& at(int index) const;
13 private:
14 int size;
15 Point *ptr;
16 };
17 vectorPoint::vectorPoint(int n) : size{n} {
18 ptr = new Point[n];
19 }
20 vectorPoint::vectorPoint(const vectorPoint &vp): size{vp.size}, ptr{new Point[size]} {
21 for(auto i = 0; i < size; ++i)
22 ptr[i] = vp.ptr[i];
23 }
24 vectorPoint::~vectorPoint() {
25 delete[] ptr;
26 }
27 int vectorPoint::get_size() const {
28 return size;
29 }
30 Point& vectorPoint::at(int index) {
31 assert(index >= 0 && index < size);
32 return ptr[index];
33 }
34 Point& vectorPoint::at(int index) const {
35 assert(index >= 0 && index < size);
36 return ptr[index];
37 }
Point.hpp
 1 #pragma once
 2 #include "point.hpp"
 3 #include <cassert>
 4 #include <iostream>
 5 class vectorPoint{
 6 public:
 7 vectorPoint(int n);
 8 vectorPoint(const vectorPoint &vp);
 9 ~vectorPoint();
10 int get_size() const;
11 Point& at(int index);
12 Point& at(int index) const;
13 private:
14 int size;
15 Point *ptr;
16 };
17 vectorPoint::vectorPoint(int n) : size{n} {
18 ptr = new Point[n];
19 }
20 vectorPoint::vectorPoint(const vectorPoint &vp): size{vp.size}, ptr{new
21 Point[size]} {
22 for(auto i = 0; i < size; ++i)
23 ptr[i] = vp.ptr[i];
24 }
25 vectorPoint::~vectorPoint() {
26 delete[] ptr;
27 }
28 int vectorPoint::get_size() const {
29 return size;
30 }
31 Point& vectorPoint::at(int index) {
32 assert(index >= 0 && index < size);
33 return ptr[index];
34 }
35 Point& vectorPoint::at(int index) const {
36 assert(index >= 0 && index < size);
37 return ptr[index];
38 }
vectorPoint.hpp

运行结果截图：

问题1：发生变化

问题2：浅复制

问题3：一般情况下，浅复制没有任何副作用，但是当类中有指针，并且此指针有动态分配空间，析构函数做了动态内存释放的处理，往往需要自定义复制构造函数，自行给指针动态分配空间，深复制。

任务4：

 1 #include <iostream>
 2 using namespace std;
 3 void swap1(int &rx, int &ry);   
 4 void swap2(int *px, int *py);   
 5 void print(int x, int y);        
 6 void test() {
 7     int x = 3, y = 4;
 8     print(x, y);
 9     swap1(x, y);       
10     print(x, y);
11 
12     cout << endl;
13 
14     x = 3, y = 4;
15     print(x, y);
16     swap2(&x, &y);       
17     print(x, y);
18 }
19 
20 int main() {
21     test();
22 }
23 
24 void swap1(int &rx, int &ry) {
25     int t;
26 
27     t = rx;  rx = ry;  ry = t;
28 }
29 
30 void swap2(int *px, int *py) {
31     int t;
32 
33     t = *px;  *px = *py;  *py = t;
34 }
35 
36 void print(int x, int y) {
37     std::cout << "x = " << x << ", y = " << y << "\n";
38 }
task4_1.cpp源码

运行结果截图： 

 1 #include <iostream>
 2 #include <typeinfo>
 3 using namespace std;
 4 
 5 int main() {
 6     int a;
 7 
 8     int &ra = a;
 9     ra = 4;
10 
11     int *pa = &a;
12     *pa = 5;
13     cout << "&a = " << hex << &a << endl;
14     cout << "&ra = " << hex << &ra << endl;
15     cout << "&pa = " << hex << &pa << "\n\n";
16     cout << "a = " << a << endl;
17     cout << "ra = " << a << endl;
18     cout << "pa = " << hex << pa << endl;
19     cout << "*pa = " << *pa << "\n\n";
20     cout << "type a: " << typeid(a).name() << endl;
21     cout << "type ra: " << typeid(ra).name() << endl;
22     cout << "type pa: " << typeid(pa).name() << endl;
23 }
task4_2.cpp源码

运行结果截图：

 1 #include <iostream>
 2 #include <vector>
 3 using namespace std;
 4 template<typename T>
 5 void output(const T &x) {
 6     for(auto i: x)
 7         std::cout << i << ", ";
 8     std::cout << "\b\b \n";
 9 }
10 template<typename T>
11 void square1(T &x) {
12     for(auto i: x) // i是普通类型
13         i *= i;
14 }
15 template<typename T>
16 void square2(T &x) {
17     for(auto &i: x)  // i是引用类型
18         i *= i;
19 }
20 void test1() {
21     vector<int> x {1, 2, 3, 4, 5};
22     cout << "动态int型数组对象x内的元素值: ";
23     output(x);
24     cout << "调用函数square1()......" << endl;
25     square1(x);
26     cout << "动态int型数组对象x内的元素值: ";
27     output(x);
28 }
29 void test2() {
30     vector<int> x {1, 2, 3, 4, 5};
31     cout << "动态int型数组对象x内的元素值: ";
32     output(x);
33     cout << "调用函数square2()......" << endl;
34     square2(x);
35     cout << "动态int型数组对象x内的元素值: ";
36     output(x);
37 }
38 int main() {
39     cout << "测试1: " << endl;
40     test1();
41     cout << "\n测试2: " << endl;
42     test2();
43 }
task4_3.cpp源码

运行结果截图：

 

指针用来表示或存储一个存储器地址，这个地址的值直接指向存在该地址的对象的值

引用是一种简单的引用数据类型，用于函数参数和返回值类型，更安全

任务5：

 1 #include<iostream>
 2 class vectorInt {
 3     public:
 4         vectorInt(int n);
 5         vectorInt(int n, int value);
 6         vectorInt(const vectorInt &v);
 7         ~vectorInt();
 8         int& at(int n);
 9         int& at(int n) const;
10         int get_size() const;
11     private:
12         int size;
13         int *s;
14 };
15 vectorInt::vectorInt(int n)
16  : size{n}, s{new int[n]} {
17     std::cout << "constructor vectorInt(int n) called. \n";
18 }
19 vectorInt::vectorInt(int n, int value)
20  : size{n}, s{new int[n]} {
21     for (int i = 0; i < n; i++)
22         s[i] = value;
23     std::cout << "constructor vectorInt(int n, int value) called. \n";
24 }
25 vectorInt::vectorInt(const vectorInt &v)
26  : size{v.size}, s{new int[v.size]} {
27     for (int i = 0; i < size; ++i)
28         s[i] = v.s[i];
29     std::cout << "copy constructor called. \n";
30 }
31 vectorInt::~vectorInt() {
32     delete[] s;
33     std::cout << "destructor called" << std::endl;
34 }
35 int vectorInt::get_size() const {
36     return size;
37 }
38 int& vectorInt::at(int n) {
39     return s[n];
40 }
41 int& vectorInt::at(int n) const {
42     return s[n];
43 }
vectorInt.hpp源码
 1 #include "vectorInt.hpp"
 2 #include <iostream>
 3 
 4 using std::cout;
 5 using std::cin;
 6 using std::endl;
 7 
 8 void output(const vectorInt &vi) {
 9     for(auto i = 0; i < vi.get_size(); ++i)
10         cout << vi.at(i) << ", ";
11     cout << "\b\b \n";
12 }
13 
14 void test() {
15     int n;
16     cout << "输入vectorInt对象中元素个数: ";
17     cin >> n;
18 
19     vectorInt x1(n);    // 构造动态int数组对象x1，包含n个元素，不对元素初始化
20     for(auto i = 0; i < n; ++i)
21         x1.at(i) = i*i;
22     cout << "vectorInt对象x1: ";
23     output(x1);
24 
25     vectorInt x2(n, 42); // 构造动态int数组对象x1，包含n个元素，每个元素初始值为42
26     cout << "vectorInt对象x2: ";
27     output(x2);
28     vectorInt x3(x2);    // 使用x2构造x3
29     cout << "vectorInt对象x3: ";
30     output(x3);
31 
32     cout << "更新vectorInt对象x2......\n";
33     x2.at(0) = 77;
34     x2.at(1) = -999;
35 
36     cout << "vectorInt对象x2: ";
37     output(x2);
38     cout << "vectorInt对象x3: ";
39     output(x3);
40 }
41 
42 int main() {
43     test();
44 }
task5.cpp源码

运行结果截图：

任务6：

 1 #pragma once
 2 
 3 #include <iostream>
 4 #include <cassert>
 5 
 6 using std::cout;
 7 using std::endl;
 8 
 9 // 类Matrix的声明
10 class Matrix {
11     public:
12         Matrix(int n, int m);       // 构造函数，构造一个n*m的矩阵
13         Matrix(int n);              // 构造函数，构造一个n*n的矩阵
14         Matrix(const Matrix &x);    // 复制构造函数， 使用已有的矩阵X构造
15         ~Matrix();
16 
17         void set(const double *pvalue);         // 用pvalue指向的连续内存块数据按行为矩阵赋值
18         void set(int i, int j, double value);   // 设置矩阵对象索引(i,j)的元素值为value
19 
20         double& at(int i, int j) const;         // 返回矩阵对象索引(i,j)的元素引用
21         double& at(int i, int j);               // 返回矩阵对象索引(i,j)的元素引用
22 
23         int get_lines() const;                  // 返回矩阵对象行数
24         int get_cols() const;                   // 返回矩阵对象列数
25 
26         void print() const;                     // 按行打印输出矩阵对象元素值
27 
28     private:
29         int lines;      // 矩阵对象内元素行数
30         int cols;       // 矩阵对象内元素列数
31         double *ptr;
32 };
33 
34 // 类Matrix的实现
35 Matrix::Matrix(int n, int m) : lines{n}, cols{m} {
36     ptr = new double[n * m];
37 }
38 Matrix::Matrix(int n) : lines{n}, cols{n} {
39     ptr = new double[n * n];
40 }
41 Matrix::Matrix(const Matrix &x) : lines{x.lines}, cols{x.cols} {
42     ptr = new double[x.lines * x.cols];
43     for (int i = 0; i < lines * cols; i++)
44         ptr[i] = x.ptr[i];
45 }
46 Matrix::~Matrix() {
47     delete[] ptr;
48 }
49 
50 void Matrix::set(const double *pvalue) {
51     for (int i = 0, j = 0; i < lines * cols; i++, j++)
52         ptr[i] = pvalue[j];
53 }
54 void Matrix::set(int i, int j, double value) {
55     ptr[i * lines + j] = value;
56 }
57 
58 double& Matrix::at(int i, int j) const {
59     return ptr[i * lines + j];
60 }
61 double& Matrix::at(int i, int j) {
62     return ptr[i * lines + j];
63 }
64 
65 int Matrix::get_lines() const {
66     return lines;
67 }
68 int Matrix::get_cols() const {
69     return cols;
70 }
71 
72 void Matrix::print() const {
73     int s = 0;
74     for (int i = 0; i < lines; i++) {
75         cout << ptr[s];
76         s++;
77         for (int j = 1; j < cols; j++, s++)
78             cout << ", " << ptr[s];
79         cout << '\n';
80     }
81 }
matrix.hpp源码
 1 #include <iostream>
 2 #include "matrix.hpp"
 3 
 4 using namespace std;
 5 
 6 const int N1 = 3;
 7 const int N2 = 2;
 8 
 9 // 输出一个矩阵对象中索引为index对应的行的所有元素值
10 void output(const Matrix &m, int index) {
11     for(auto j = 0; j < m.get_cols(); ++j)
12         cout << m.at(index, j) << ", ";
13     cout << "\b\b \n";
14 }
15 
16 void test() {
17 
18 
19     double x[N1*N2] = {3, 1, 4, 1, 5, 9};
20 
21     Matrix m1(N1, N2);      // 创建一个N1×N2矩阵
22     m1.set(x);              // 用一维数组x的值按行为矩阵m1赋值
23     cout << "矩阵对象m1: " << endl;
24     m1.print();             // 打印矩阵m1的值
25     cout << "矩阵对象m1第0行是: " << endl;
26     output(m1, 0);
27     cout << endl;
28 
29     Matrix m2(N2, N1);
30     m2.set(x);
31     cout << "矩阵对象m2: " << endl;
32     m2.print();
33     cout << "矩阵对象m2第0行是: " << endl;
34     output(m2, 0);
35     cout << endl;
36 
37     Matrix m3(m2);      // 用矩阵m2构造新的矩阵m3
38     m3.set(0, 0, 999);  // 讲矩阵对象m2索引(0,0)元素设为999
39     cout << "矩阵对象m3:" << endl;
40     m3.print();
41     cout << endl;
42 
43     Matrix m4(2);       // 创建一个2*2矩阵对象
44     m4.set(x);          // 用一维数组x的值按行为矩阵m4赋值
45     cout << "矩阵对象m4:" << endl;
46     m4.print();
47 }
48 
49 int main() {
50     test();
51 }
task6.cpp源码

运行结果截图：

 

 

posted on 2023-11-06 03:56  陈少秋  阅读(6)  评论(0)  编辑  收藏  举报
 
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