实验四

任务五：

vectorlnt.h

#pragma once
#include<iostream>
using std::cout;
using std::cin;
using std::endl;
class vectorlnt
{
    friend void output(const vectorlnt& obj);
public:
    vectorlnt(int n);
    vectorlnt(int n, int val);
    vectorlnt(const vectorlnt& obj);
    int& at(int index);
    ~vectorlnt();
private:
    int size;
    int* data;
};
vectorlnt::vectorlnt(int n)
{
    data = new int[n];
    size = n;
    cout << "构造1" << endl;
}
vectorlnt::vectorlnt(int n, int val)
{
    data = new int[n];
    size = n;
    for (int i = 0; i < n; i++)
        data[i] = val;
    cout << "构造2" << endl;
}
vectorlnt::vectorlnt(const vectorlnt& obj)
{
    data = new int[obj.size];
    size = obj.size;
    for (int i = 0; i < obj.size; i++)
        data[i] = obj.data[i];
    cout << "复制构造" << endl;
}
int& vectorlnt::at(int index)
{
    return data[index];
}
vectorlnt::~vectorlnt()
{
    size = 0;
    delete [] data;
    data = nullptr;
    cout << "析构" << endl;
}
void output(const vectorlnt& obj)
{
    for (int i = 0; i < obj.size; i++)
    {
        cout << obj.data[i] << " ";
    }
    cout << endl;
}

main.h

#include <iostream>
#include "vectorlnt.h"
using namespace std;
void test() {
    using namespace std;

    int n;
    cin >> n;

    vectorlnt x1(n);
    for (auto i = 0; i < n; ++i)
        x1.at(i) = i * i;

    output(x1);

    vectorlnt x2(n, 42);
    vectorlnt x3(x2);

    output(x2);
    output(x3);

    x2.at(0) = 77;

    output(x2);
    output(x3);
}

int main() {
    test();
}

 任务五

matrix.h

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

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

    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); //设置矩阵第i行第j列元素值为value
    double& at(int i, int j);          //返回矩阵第i行第j列元素的引用
    double at(int i, int j) const;     // 返回矩阵第i行第j列元素的值
    int get_lines() const;             //返回矩阵行数
    int get_cols() const;              //返回矩列数
    void print() const;                // 按行打印输出矩阵

private:
    int lines; // 矩阵行数
    int cols;  // 矩阵列数
    double* p; // 指向存放矩阵数据的内存块的首地址
};
Matrix::Matrix(int n)
{
    p = new double [n * n];
    lines = cols = n;
}
Matrix::Matrix(int n, int m)
{
    p = new double[n * m];
    lines = n;
    cols = m;
}
Matrix::Matrix(const Matrix& x)
{
    p = new double[x.lines * x.cols];
    lines = x.lines;
    cols = x.cols;
    for (int i = 0; i < x.lines; i++)
    {
        for (int j = 0; j < x.cols; j++)
        {
            p[i * x.cols + j] = x.p[i * x.cols + j];
        }
    }
}
Matrix::~Matrix()
{
    delete[] p;
    p = nullptr;
    lines = cols = 0;
}
void Matrix::set(const double* pvalue)
{
    int size = lines * cols;
    for (int i = 0; i < size; i++)
        p[i] = pvalue[i];
}
void Matrix::set(int i, int j, double value)
{
    p[i * cols + j] = value;
}
double& Matrix::at(int i, int j)
{
    return p[i * cols + j];
}
double Matrix::at(int i, int j)const 
{
    return p[i * cols + j];
}
int Matrix::get_lines()const
{
    return lines;
}
int Matrix::get_cols()const {
    return cols;
}
void Matrix::print()const {
    for (int i = 0; i < lines; i++)
    {
        for (int j = 0; j < cols; j++)
        {
            cout << p[i * cols + j] << " ";
        }
        cout << endl;
    }
}

main.cpp

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

void test() {
    using namespace std;

    double x[] = { 6, 5, 4, 3, 2, 1 };

    Matrix m1(3, 2);    // 创建一个3×2的矩阵
    m1.set(x);          // 用一维数组x的值按行为矩阵m1赋值
    m1.print();         // 打印矩阵m1的值
    cout << "the first line is: " << endl;
    cout << m1.at(0, 0) << " " << m1.at(0, 1) << endl;  // 输出矩阵m1第1行两个元素的值
    cout << endl;

    Matrix m2(2, 3);
    m2.set(x);
    m2.print();
    cout << "the first line is: " << endl;
    cout << m2.at(0, 0) << " " << m2.at(0, 1) << " " << m2.at(0, 2) << endl;
    cout << endl;

    Matrix m3(m2);      // 用矩阵m2构造新的矩阵m3
    m3.set(0, 0, 999);  // 将矩阵m3第0行第0列元素值设为999
    m3.print();
}

int main() {
    test();
}