实验3 类和对象II

实验任务4

• vector_int.hpp

#ifndef VECTOR_INT_HPP
#define VECTOR_INT_HPP
#include <iostream>
#include <cassert>
using namespace std;
class Vector_int
{
    public:
        Vector_int(int n);
        Vector_int(int n,int v);
        Vector_int(const Vector_int &x);
        ~Vector_int()
        {
            cout<<"deleting..."<<endl;
            delete[] p;
        };
        int &at(int index);
    private:
        int size;
        int value;
        int index;
        int *p;
};
Vector_int::Vector_int(int n):size(n)
{
    cout<<"dynamic create array..."<<endl;
    p=new int[n];
    for(int x=0;x<size;x++)
    {
        p[x]=0;
    }
}
Vector_int::Vector_int(int n,int v):size(n),value(v)
{
    cout<<"dynamic create array with value..."<<endl;
    p=new int[n];
    for(int x=0;x<size;x++)
    {
        p[x]=value;
    }
}
Vector_int::Vector_int(const Vector_int &x):size(x.size)
{
    cout<<"deep-copy create array..."<<endl;
    p=new int[size];
    for(int i=0;i<size;i++)
    {
        p[i]=x.p[i];
    }
}
int &Vector_int::at(int index)
{
    assert(index>=0&&index<size);
    return p[index];
}
#endif

• task4.cpp

#include <iostream>
#include "vector_int.hpp"
/* run this program using the console pauser or add your own getch, system("pause") or input loop */
using namespace std;

int main() {
    int n;
    cout<<"请输入n的值："<<endl;
    cin>>n;
    Vector_int x(n);
    cout<<"x.at(0)="<<x.at(0)<<endl;
    Vector_int z(n,6);
    cout<<"z.at(0)="<<z.at(0)<<endl;
    Vector_int y(x);
    y.at(0)=999;
    cout<<"y.at(0)="<<y.at(0)<<endl;
}

• 运行测试结果：

 

实验任务5

• 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(){delete[] p;};                         //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, int 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):lines(n),cols(n)
{
    p=new double[lines*cols];
}

Matrix::Matrix(int n,int m):lines(n),cols(m)
{
    p=new double[lines*cols];
}

Matrix::Matrix(const Matrix &X):lines(X.lines),cols(X.cols)
{
    p=new double[lines*cols];
    for (auto i=0;i<lines*cols;i++)
    {
        p[i]=X.p[i];
    }
}

void Matrix::set(const double *pvalue)
{
    int x=0;
    for (auto i=0;i<lines*cols;i++)
    {
        p[i]=pvalue[x++];    
    }
}

void Matrix::set(int i, int j, int 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
{
    using namespace std;
    for(int i=0;i<lines*cols;i++)
    {
        cout<<p[i];
        if((i+1)%cols==0&&i!=0)
        {
            cout<<endl;
        }
        else
        {
            cout<<",";
        }
    }
}
#endif

• task5.cpp

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

int main()
{
    using namespace std;

    double x[] = {2,4,6,8,10,12};

    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;
    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);
    m3.set(0, 0, 888);
    m3.print();
}

• 运行测试结果：