实验三

1.

.hpp

#pragma once

#include <iostream>
using std::cout;
using std::endl;

class Point {
public:
    Point(int x0 = 0, int y0 = 0);
    ~Point() = default;

    int get_x() const;
    int get_y() const;
    void show() const;
    void move(int new_x, int new_y);

private:
    int x, y;
};

Point::Point(int x0, int y0): x{x0}, y{y0} {
}

int Point::get_x() const {
    return x;
}

int Point::get_y() const {
    return y;
}

void Point::show() const {
    cout << "(" << x << ", " << y << ")" << endl;
}

void Point::move(int new_x, int new_y) {
    x = new_x;
    y = new_y;
}

.cpp

#include <iostream>
#include "point.hpp"
#include <vector>

using std::vector;
using std::cin;

// 输出vector<Point>对象内所有点的坐标
void output(const vector<Point> &v) {
    for(auto &t: v)
        t.show();
}

void test() {
    int n;
    cout << "输入动态Point数组类对象中元素个数: ";
    cin >> n;

    vector<Point> x(n);
    cout << "x对象中所有点坐标信息: " << endl;
    output(x);

    vector<Point> y(x);  // 基于vector<Point>对象x构建对象y
    cout << "\nx对象中所有点坐标信息: " << endl;
    output(y);

    cout << "\n更新x对象......" << endl;
    x.at(0).move(30, 50);       // 更新对象x内索引为0的点对象坐标
    x.push_back(Point(2, 2));   // 向x对象末尾添加一个点对象

    cout << "\nx对象中所有点坐标信息: " << endl;
    output(x);
    cout << "\ny对象中所有点坐标信息: " << endl;
    output(y);
}

int main() {
    test();
}

不发生变化；

深复制。

2.

.hpp

#pragma once

#include <iostream>
using std::cout;
using std::endl;

class Point {
public:
    Point(int x0 = 0, int y0 = 0);
    ~Point() = default;

    int get_x() const;
    int get_y() const;
    void show() const;
    void move(int new_x, int new_y);

private:
    int x, y;
};

Point::Point(int x0, int y0): x{x0}, y{y0} {
}

int Point::get_x() const {
    return x;
}

int Point::get_y() const {
    return y;
}

void Point::show() const {
    cout << "(" << x << ", " << y << ")" << endl;
}

void Point::move(int new_x, int new_y) {
    x = new_x;
    y = new_y;
}

.hpp

#pragma once

#include "point.hpp"
#include <cassert>
#include <iostream>

class vectorPoint{
public:
    vectorPoint(int n);
    ~vectorPoint();

    int get_size() const;           // 获得当前动态数组内元素个数
    Point& at(int index);           // 返回下标为index的元素引用
    Point& at(int index) const;     // 返回下标为index的元素const引用

private:
    int size; // 动态数组的大小
    Point *ptr;
};

vectorPoint::vectorPoint(int n) : size{n} {
    ptr = new Point[n];
}

vectorPoint::~vectorPoint() {
    delete[] ptr;
}

int vectorPoint::get_size() const {
    return size;
}

Point& vectorPoint::at(int index) {
    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
    return ptr[index];
}

Point& vectorPoint::at(int index) const {
    assert(index >= 0 && index < size);
    return ptr[index];
}

.cpp

#include "vectorPoint.hpp"
#include <iostream>

// 输出vectorPoint对象内的所有数据
void output(const vectorPoint &v) {
    for(auto i = 0; i < v.get_size(); ++i)
        v.at(i).show();
}

// 测试vectorPoint类：构造对象、复制构造对象
void test() {
    using namespace std;

    int n;
    cout << "输入vectorPoint对象中元素个数: ";
    cin >> n;

    vectorPoint x(n);
    cout << "x对象中所有点坐标信息: " << endl;
    output(x);

    vectorPoint y(x);
    cout << "\ny对象中所有点坐标信息: " << endl;
    output(y);

    cout << "\n更新x对象中点坐标信息......" << endl;
    x.at(0).move(30, 50);
    x.at(1).move(-1, -1);

    cout << "x对象中所有点坐标信息: " << endl;
    output(x);

    cout << "\ny对象中所有点坐标信息: " << endl;
    output(y);
}

int main() {
    test();
}

发生变化；

浅复制；

浅复制。

3.

.hpp

#pragma once

#include <iostream>
using std::cout;
using std::endl;

class Point {
public:
    Point(int x0 = 0, int y0 = 0);
    ~Point() = default;

    int get_x() const;
    int get_y() const;
    void show() const;
    void move(int new_x, int new_y);

private:
    int x, y;
};

Point::Point(int x0, int y0): x{x0}, y{y0} {
}

int Point::get_x() const {
    return x;
}

int Point::get_y() const {
    return y;
}

void Point::show() const {
    cout << "(" << x << ", " << y << ")" << endl;
}

void Point::move(int new_x, int new_y) {
    x = new_x;
    y = new_y;
}

 

.hpp

#pragma once

#include "point.hpp"
#include <cassert>
#include <iostream>

class vectorPoint{
public:
    vectorPoint(int n);
    vectorPoint(const vectorPoint &vp);
    ~vectorPoint();

    int get_size() const;           // 获得当前动态数组内元素个数
    Point& at(int index);           // 返回下标为index的元素引用
    Point& at(int index) const;     // 返回下标为index的元素const引用

private:
    int size; // 动态数组的大小
    Point *ptr;
};

vectorPoint::vectorPoint(int n) : size{n} {
    ptr = new Point[n];
}

vectorPoint::vectorPoint(const vectorPoint &vp): size{vp.size}, ptr{new Point[size]} {
    for(auto i = 0; i < size; ++i)
        ptr[i] = vp.ptr[i];
}

vectorPoint::~vectorPoint() {
    delete[] ptr;
}

int vectorPoint::get_size() const {
    return size;
}

Point& vectorPoint::at(int index) {
    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
    return ptr[index];
}

Point& vectorPoint::at(int index) const {
    assert(index >= 0 && index < size);
    return ptr[index];
}

.cpp

#include "vectorPoint.hpp"
#include <iostream>

// 输出vectorPoint对象内的所有数据
void output(const vectorPoint &v) {
    for(auto i = 0; i < v.get_size(); ++i)
        v.at(i).show();
}

// 测试vectorPoint类：构造对象、复制构造对象
void test() {
    using namespace std;

    int n;
    cout << "输入vectorPoint对象中元素个数: ";
    cin >> n;

    vectorPoint x(n);
    cout << "x对象中所有点坐标信息: " << endl;
    output(x);

    vectorPoint y(x);
    cout << "\ny对象中所有点坐标信息: " << endl;
    output(y);

    cout << "\n更新x对象中点坐标信息......" << endl;
    x.at(0).move(30, 50);
    x.at(1).move(-1, -1);

    cout << "x对象中所有点坐标信息: " << endl;
    output(x);

    cout << "\ny对象中所有点坐标信息: " << endl;
    output(y);
}

int main() {
    test();
}

不发生变化；

深复制；

当类的成员中包含指针域成员时，默认复制构造函数进行浅复制。浅复制仅复制指针，新指针与原指针指向同一内存区域；深复制复制数据并为之分配单独的内存区域，新指针指向新的内存区域。

4.

.cpp

#include <iostream>
using namespace std;

// 函数声明
void swap1(int &rx, int &ry);    // 引用作为形参
void swap2(int *px, int *py);    // 指针作为形参
void print(int x, int y);        // 普通变量作为形参

// 测试代码
void test() {
    int x = 3, y = 4;

    print(x, y);
    swap1(x, y);        // 函数调用，注意：引用作为形参时，实参形式
    print(x, y);

    cout << endl;

    x = 3, y = 4;
    print(x, y);
    swap2(&x, &y);        // 函数调用，注意：指针作为形参时，实参形式
    print(x, y);
}

int main() {
    test();
}

// 函数定义：交换两个变量（引用变量作为形参）
void swap1(int &rx, int &ry) {
    int t;

    t = rx;  rx = ry;  ry = t;
}

// 函数定义：交换两个变量（指针变量作为形参）
void swap2(int *px, int *py) {
    int t;

    t = *px;  *px = *py;  *py = t;
}

// 函数定义：输出两个变量（普通变量作为形参）
void print(int x, int y) {
    std::cout << "x = " << x << ", y = " << y << "\n";
}

.cpp

#include <iostream>
#include <typeinfo>
using namespace std;

int main() {
    int a;

    int &ra = a;
    ra = 4;

    int *pa = &a;
    *pa = 5;

    // 以十六进制形式输出普通变量a, 引用变量ra，指针变量pa的地址
    cout << "&a = " << hex << &a << endl;
    cout << "&ra = " << hex << &ra << endl;
    cout << "&pa = " << hex << &pa << "\n\n";

    // 输出普通变量a, 引用变量ra，指针变量pa的值
    cout << "a = " << a << endl;
    cout << "ra = " << a << endl;
    cout << "pa = " << hex << pa << endl;

    // 输出指针变量pa指向的变量的值
    cout << "*pa = " << *pa << "\n\n";

    // 输出普通变量a，引用变量ra, 指针变量pa的类型信息
    cout << "type a: " << typeid(a).name() << endl;
    cout << "type ra: " << typeid(ra).name() << endl;
    cout << "type pa: " << typeid(pa).name() << endl;
}

.cpp

#include <iostream>
#include <vector>

using namespace std;

template<typename T>
void output(const T &x) {
    for(auto i: x)
        std::cout << i << ", ";
    std::cout << "\b\b \n";
}

template<typename T>
void square1(T &x) {
    for(auto i: x) // i是普通类型
        i *= i;
}

template<typename T>
void square2(T &x) {
    for(auto &i: x)  // i是引用类型
        i *= i;
}

void test1() {
    vector<int> x {1, 2, 3, 4, 5};

    cout << "动态int型数组对象x内的元素值: ";
    output(x);

    cout << "调用函数square1()......" << endl;
    square1(x);

    cout << "动态int型数组对象x内的元素值: ";
    output(x);
}

void test2() {
    vector<int> x {1, 2, 3, 4, 5};

    cout << "动态int型数组对象x内的元素值: ";
    output(x);

    cout << "调用函数square2()......" << endl;
    square2(x);

    cout << "动态int型数组对象x内的元素值: ";
    output(x);
}

int main() {
    cout << "测试1: " << endl;
    test1();

    cout << "\n测试2: " << endl;
    test2();
}

指针类型：本质是地址，可以独立存在，用于存放数据的地址。可以对指针本身进行操作，也可以通过指针去间接操作数据。引用类型：本质是别名，不能独立存在，依赖于源数据。所有操作同步反馈到源数据上。

 5.

.hpp

#include<iostream>
class vectorInt {
    public:
        vectorInt(int n);
        vectorInt(int n, int value);
        vectorInt(const vectorInt &v);
        ~vectorInt();
        int& at(int n);
        int& at(int n) const;
        int get_size() const;
    private:
        int size;
        int *s;
};
vectorInt::vectorInt(int n)
 : size{n}, s{new int[n]} {
    std::cout << "constructor vectorInt(int n) called. \n";
}
vectorInt::vectorInt(int n, int value)
 : size{n}, s{new int[n]} {
    for (int i = 0; i < n; i++)
        s[i] = value;
    std::cout << "constructor vectorInt(int n, int value) called. \n";
}
vectorInt::vectorInt(const vectorInt &v)
 : size{v.size}, s{new int[v.size]} {
    for (int i = 0; i < size; ++i)
        s[i] = v.s[i];
    std::cout << "copy constructor called. \n";
}
vectorInt::~vectorInt() {
    delete[] s;
    std::cout << "destructor called" << std::endl;
}
int vectorInt::get_size() const {
    return size;
}
int& vectorInt::at(int n) {
    return s[n];
}
int& vectorInt::at(int n) const {
    return s[n];
}

.cpp

#include "vectorInt.hpp"
#include <iostream>

using std::cout;
using std::cin;
using std::endl;

void output(const vectorInt &vi) {
    for(auto i = 0; i < vi.get_size(); ++i)
        cout << vi.at(i) << ", ";
    cout << "\b\b \n";
}

void test() {
    int n;
    cout << "输入vectorInt对象中元素个数: ";
    cin >> n;

    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
    for(auto i = 0; i < n; ++i)
        x1.at(i) = i*i;
    cout << "vectorInt对象x1: ";
    output(x1);

    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
    cout << "vectorInt对象x2: ";
    output(x2);
    vectorInt x3(x2);    // 使用x2构造x3
    cout << "vectorInt对象x3: ";
    output(x3);

    cout << "更新vectorInt对象x2......\n";
    x2.at(0) = 77;
    x2.at(1) = -999;

    cout << "vectorInt对象x2: ";
    output(x2);
    cout << "vectorInt对象x3: ";
    output(x3);
}

int main() {
    test();
}

6.

.hpp

#pragma once

#include <iostream>
#include <cassert>

using std::cout;
using std::endl;

// 类Matrix的声明
class Matrix {
    public:
        Matrix(int n, int m);       // 构造函数，构造一个n*m的矩阵
        Matrix(int n);              // 构造函数，构造一个n*n的矩阵
        Matrix(const Matrix &x);    // 复制构造函数， 使用已有的矩阵X构造
        ~Matrix();

        void set(const double *pvalue);         // 用pvalue指向的连续内存块数据按行为矩阵赋值
        void set(int i, int j, double value);   // 设置矩阵对象索引(i,j)的元素值为value

        double& at(int i, int j) const;         // 返回矩阵对象索引(i,j)的元素引用
        double& at(int i, int j);               // 返回矩阵对象索引(i,j)的元素引用

        int get_lines() const;                  // 返回矩阵对象行数
        int get_cols() const;                   // 返回矩阵对象列数

        void print() const;                     // 按行打印输出矩阵对象元素值

    private:
        int lines;      // 矩阵对象内元素行数
        int cols;       // 矩阵对象内元素列数
        double *ptr;
};

// 类Matrix的实现
Matrix::Matrix(int n, int m) : lines{n}, cols{m} {
    ptr = new double[n * m];
}
Matrix::Matrix(int n) : lines{n}, cols{n} {
    ptr = new double[n * n];
}
Matrix::Matrix(const Matrix &x) : lines{x.lines}, cols{x.cols} {
    ptr = new double[x.lines * x.cols];
    for (int i = 0; i < lines * cols; i++)
        ptr[i] = x.ptr[i];
}
Matrix::~Matrix() {
    delete[] ptr;
}

void Matrix::set(const double *pvalue) {
    for (int i = 0, j = 0; i < lines * cols; i++, j++)
        ptr[i] = pvalue[j];
}
void Matrix::set(int i, int j, double value) {
    ptr[i * lines + j] = value;
}

double& Matrix::at(int i, int j) const {
    return ptr[i * lines + j];
}
double& Matrix::at(int i, int j) {
    return ptr[i * lines + j];
}

int Matrix::get_lines() const {
    return lines;
}
int Matrix::get_cols() const {
    return cols;
}

void Matrix::print() const {
    int s = 0;
    for (int i = 0; i < lines; i++) {
        cout << ptr[s];
        s++;
        for (int j = 1; j < cols; j++, s++)
            cout << ", " << ptr[s];
        cout << '\n';
    }
}

.cpp

#include <iostream>
#include "matrix.hpp"

using namespace std;

const int N1 = 3;
const int N2 = 2;

// 输出一个矩阵对象中索引为index对应的行的所有元素值
void output(const Matrix &m, int index) {
    for(auto j = 0; j < m.get_cols(); ++j)
        cout << m.at(index, j) << ", ";
    cout << "\b\b \n";
}

void test() {


    double x[N1*N2] = {3, 1, 4, 1, 5, 9};

    Matrix m1(N1, N2);      // 创建一个N1×N2矩阵
    m1.set(x);              // 用一维数组x的值按行为矩阵m1赋值
    cout << "矩阵对象m1: " << endl;
    m1.print();             // 打印矩阵m1的值
    cout << "矩阵对象m1第0行是: " << endl;
    output(m1, 0);
    cout << endl;

    Matrix m2(N2, N1);
    m2.set(x);
    cout << "矩阵对象m2: " << endl;
    m2.print();
    cout << "矩阵对象m2第0行是: " << endl;
    output(m2, 0);
    cout << endl;

    Matrix m3(m2);      // 用矩阵m2构造新的矩阵m3
    m3.set(0, 0, 999);  // 讲矩阵对象m2索引(0,0)元素设为999
    cout << "矩阵对象m3:" << endl;
    m3.print();
    cout << endl;

    Matrix m4(2);       // 创建一个2*2矩阵对象
    m4.set(x);          // 用一维数组x的值按行为矩阵m4赋值
    cout << "矩阵对象m4:" << endl;
    m4.print();
}

int main() {
    test();
}