实验任务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);
cout << "\ny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);
x.push_back(Point(2, 2));
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();
}
问题1:对x对象进行更新时,基于vector<point>对象x创建的对象y是否发生变化? 否
问题2:标准库模板类vector在复制一个动态数组对象时,实现的是深复制还是浅复制? 深复制
实验任务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; Point& at(int index); Point& at(int index) const; private: int size; 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); return ptr[index]; } Point& vectorPoint::at(int index) const { assert(index >= 0 && index < size); return ptr[index]; }
task2.cpp
#include "vectorpoint.hpp" #include <iostream> void output(const vectorPoint &v) { for(auto i = 0; i < v.get_size(); ++i) v.at(i).show(); } 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(); }
问题1:观察更新对象x后,基于vectorpoint对象x创建的对象y是否发生变化? 是
问题2:编译器为vectorpoint类创建的默认复制构造函数,在复制一个动态数组对象时,实现的是深复制还是浅复制? 浅复制
问题3:在类vectorpoint内部,手动增加以下复制构造函数声明和定义,实现的是浅复制还是深复制? 浅复制
实验任务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; Point& at(int index); Point& at(int index) const; private: int size; 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); return ptr[index]; } Point& vectorPoint::at(int index) const { assert(index >= 0 && index < size); return ptr[index]; }
task3.cpp
#include "vectorpoint.hpp" #include <iostream> void output(const vectorPoint &v) { for(auto i = 0; i < v.get_size(); ++i) v.at(i).show(); } 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(); }
问题1:观察更新对象x后,基于vectorPoint对象x创建的对象y是否发生变化? 否
问题2:这个vectorPoint类的实现中,复制构造函数实现的是深复制还是浅复制? 深复制
问题3:基于实验任务2和3,总结当类的成员中包含指针域成员时深复制与浅复制的区别。
浅复制:只复制指针本身,而不复制指针指向的内存区域。这意味着如果两个对象都包含指向同一个对象的指针,那么浅复制后这两个对象将共享同一个对象。这可能会导致一些问题,例如当一个对象修改指向的对象时,另一个对象也会受到影响。
深复制:不仅复制指针本身,还复制指针指向的内存区域。深复制确保每个对象都有自己独立的副本,不会出现共享同一个对象的问题。
task4_1.cpp
#include <iostream> using namespace std; void swap1(int &rx, int &ry); void swap2(int *px, int *py); void print(int x, int y); void test() { int x = 3, y = 4; print(x, y); swap1(x, y); print(x, y); cout << endl; x = 3, y = 4; print(x, y); swap2(&x, &y); print(x, y); } int main() { test(); } void swap1(int &rx, int &ry) { int t; t = rx; rx = ry; ry = t; } void swap2(int *px, int *py) { int t; t = *px; *px = *py; *py = t; } void print(int x, int y) { std::cout << "x = " << x << ", y = " << y << "\n"; }
task4_2.cpp
#include <iostream> #include <typeinfo> using namespace std; int main() { int a; int &ra = a; ra = 4; int *pa = &a; *pa = 5; cout << "&a = " << hex << &a << endl; cout << "&ra = " << hex << &ra << endl; cout << "&pa = " << hex << &pa << "\n\n"; cout << "a = " << a << endl; cout << "ra = " << a << endl; cout << "pa = " << hex << pa << endl; cout << "*pa = " << *pa << "\n\n"; cout << "type a: " << typeid(a).name() << endl; cout << "type ra: " << typeid(ra).name() << endl; cout << "type pa: " << typeid(pa).name() << endl; }
task4_3
#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 *= i; } template<typename T> void square2(T &x) { for(auto &i: x) 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(); }
问题1:用文字总结引用类型、指针类型的区别。
引用类型是一个变量的别名,它是对已存在变量的间接引用。引用类型在声明时必须初始化,并且在整个程序生命周期内不能更改。它不能独立存在,必须与被引用的变量绑定在一起。引用类型可以用来访问和修改被引用的变量的值。
指针类型是一个存储变量地址的类型。指针类型在声明时不一定要初始化,但在使用前必须指向一个已存在的变量。它可以独立存在。
task5
#include <iostream> #include "vectorInt.hpp" using std::cout; using std::cin; using std::endl; void output(const vectorInt& x) { for (int i = 0; i < x.get_size(); ++i) { cout << x.at(i) << " "; } cout << endl; } void test() { int n; cout << "输入vectorInt对象中元素个数: "; cin >> n; vectorInt x1(n); for(auto i = 0; i < n; ++i) x1.at(i) = i*i; cout << "vectorInt对象x1: "; output(x1); vectorInt x2(n, 42); cout << "vectorInt对象x2: "; output(x2); vectorInt x3(x2); 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(); }
#include <iostream> using namespace std; class vectorInt { public: vectorInt(int size, int value = 0) { cout << "Constructor called, size = " << size << ", value = " << value << endl; data = new int[size]; for (int i = 0; i < size; ++i) { data[i] = value; } } vectorInt(const vectorInt& x) { cout << "Copy constructor called" << endl; data = new int[x.size()]; for (int i = 0; i < x.size(); ++i) { data[i] = x.data[i]; } } ~vectorInt() { cout << "Destructor called" << endl; delete[] data; } int at(int i) const { if (i >= 0 && i < size()) { return data[i]; } else { throw out_of_range("Index out of range"); } } int get_size() const { return size_; } void output() const { for (int i = 0; i < size(); ++i) { cout << data[i] << " "; } cout << endl; } private: int* data; int size_; int size() const { return size_; } };
task6
matrix.hpp
#pragma once #include <iostream> #include <vector> class Matrix { public: Matrix(int rows, int cols); Matrix(const std::vector<std::vector<int>>& data); int getRows() const; int getCols() const; const std::vector<int>& getRow(int row) const; const std::vector<std::vector<int>>& getData() const; void setData(const std::vector<std::vector<int>>& data); private: int rows; int cols; std::vector<std::vector<int>> data; }; Matrix::Matrix(int rows, int cols) : rows(rows), cols(cols) { data.resize(rows, std::vector<int>(cols, 0)); } Matrix::Matrix(const std::vector<std::vector<int>>& data) : data(data) { rows = data.size(); cols = data[0].size(); } int Matrix::getRows() const { return rows; } int Matrix::getCols() const { return cols; } const std::vector<int>& Matrix::getRow(int row) const { return data[row]; } const std::vector<std::vector<int>>& Matrix::getData() const { return data; } void Matrix::setData(const std::vector<std::vector<int>>& data) { this->data = data; rows = data.size(); cols = data[0].size(); }
#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] = {1, 2, 3, 4, 5, 6}; 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(); }
标签:std,const,vectorPoint,Point,int,实验,数组,size,指针 From: https://www.cnblogs.com/yzsya/p/17797441.html