实验三 类和对象Ⅱ

任务4 源代码

vector_int.hpp

#pragma once
#include <iostream>
#include <cassert>

class Vector_int
{
public:
    Vector_int(int n, int init_num = 0);
    Vector_int(const Vector_int &vec0);
    ~Vector_int();
    int& at(int pos);

private: 
    int *vec;
    int capacity;
};

Vector_int::Vector_int(int n, int init_num): capacity(n)
{
    std::cout << "constructor called" << std::endl;
    this->vec = new int[this->capacity];
    for (int i = 0; i < this->capacity; i++)
        this->vec[i] = init_num;
}
Vector_int::Vector_int(const Vector_int &vec0)
{
    std::cout << "copy_constructor called" << std::endl;
    this->capacity = vec0.capacity;
    this->vec = new int[this->capacity];
    for (int i = 0; i < this->capacity; i++)
        this->vec[i] = vec0.vec[i];
}
Vector_int::~Vector_int()
{
    std::cout << "destructor called" << std::endl;
    delete[] this->vec;
    this->vec = nullptr;
    this->capacity = 0;
}
int& Vector_int::at(int pos)
{
    assert(pos < this->capacity);
    return this->vec[pos];
}

task4.cpp

#include "vector_int.hpp"

int main()
{
    int n = 10;

    Vector_int x1(n);

    Vector_int x2(n, 6);

    Vector_int y(x2);

    y.at(0) = 999;

    for (int i = 0; i < n; i++)
        std::cout << x1.at(i) << " ";
    std::cout << std::endl;
    for (int i = 0; i < n; i++)
        std::cout << x2.at(i) << " ";
    std::cout << std::endl;
    for (int i = 0; i < n; i++)
        std::cout << y.at(i) << " ";
    std::cout << std::endl;
    
    return 0;
}

任务5 源代码

Matrix.hpp

#ifndef MATRIX_H
#define MATRIX_H

#include <iostream>
#include <cassert>

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
};


// 类Matrix的实现：待补足
// ×××
Matrix::Matrix(int n): lines(n), cols(n)
{
    this->p = new double[this->lines * this->cols];
}
Matrix::Matrix(int n, int m): lines(n), cols(m)
{
    this->p = new double[this->lines * this->cols];
}
Matrix::Matrix(const Matrix &X): lines(X.lines), cols(X.cols)
{
    this->p = new double[this->lines * this->cols];
    for (int i = 0; i < this->lines * this->cols; i++)
        p[i] = X.p[i];
}
Matrix::~Matrix()
{
    delete[] this->p;
    this->p = nullptr;
}
void Matrix::set(const double *pvalue)
{
    int tail = 0;
    for (int i = 0; i < this->lines * this->cols; i++)
        p[i] = pvalue[tail++];
}
void Matrix::set(int i, int j, double value)
{
    p[i * this->cols + j] = value;
}
double& Matrix::at(int i, int j)
{
    return p[i * this->cols + j];
}
double Matrix::at(int i, int j) const
{
    return p[i * this->cols + j];
}
int Matrix::get_lines() const
{
    return this->lines;
}
int Matrix::get_cols() const
{
    return this->cols;
}
void Matrix::print() const
{
    for (int i = 0; i < this->lines; i++)
    {
        for (int j = 0; j < this->cols; j++)
            std::cout << this->p[i * this->cols + j] << " ";
        std::cout << std::endl;
    }
}

#endif

task5.cpp

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

int main()
{
    using namespace std;

    double x[] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12};

    Matrix m1(3, 4);    // 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;
    for (int i = 0; i < 4; i++)
        cout << m1.at(0, i) << " ";
    cout << endl
         << endl;

    Matrix m2(4, 3);
    m2.set(x);
    m2.print();
    cout << "the first line is: " << endl;
    for (int i = 0; i < 3; i++)
        cout << m2.at(0, i) << " ";
    cout << endl
         << endl;
    
    Matrix m3(m2);
    m3.set(0, 0, 999);
    m3.print();
}