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类与数组、指针

时间:2023-11-05 23:13:31浏览次数:31  
标签:const cout Point int void vectorPoint 数组 指针

任务1

point.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;
}

task.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();
}

运行结果:

 不发生变化;

深复制。

任务2

point.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;
}

vectorPoint.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];
}

task.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();
}
实验结果

发生变化;

浅复制;

浅复制。

任务3

point.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;
}

vectorpoint.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];
}

task.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()

}

实验结果

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。

任务4

task1.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 << ";

}

实验结果

 

task2.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;
}

实验结果

task3.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();
}

实验结果

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。

任务5

.hpp

#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();
}

.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();
}

实验结果

任务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();
}

实验结果

实验总结:

通过这次实验,我知道了什么是深复制、浅复制,能根据问题场景合理编码(复制构造函数)实现深复制

了解了重载成员函数、返回引用类型等用法

 



标签:const,cout,Point,int,void,vectorPoint,数组,指针
From: https://www.cnblogs.com/lwjddd/p/17811483.html

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