实验4 类与数组

实验任务5

#pragma once

#include<iostream>
#include<cassert>
using std::cout;
using std::endl;

class vectorInt
{
private:
    /* data */
    int size;
    int *p;
public:
    vectorInt(int n);
    vectorInt(int n, int value);
    vectorInt(const vectorInt &ve);
    ~vectorInt();

    int &at(int index);
    int get_size() const;
    friend void output(vectorInt &v);
};

vectorInt::vectorInt(int s)
{
    size = s;
    p = new int[size];
    cout << "constructor 1 called" << endl;
}

vectorInt::vectorInt(int s, int value)
{
    size = s;
    p = new int[size];
    for(auto i = 0; i < size; i++)
        p[i] = value;
    cout << "constructor 2 called" << endl;    
}

vectorInt::vectorInt(const vectorInt &ve){
    size = ve.size;
    p = new int[size];
    for(auto i = 0; i < size; i++)
        p[i] = ve.p[i];
    cout << "copy constructor called" << endl;    
}

vectorInt::~vectorInt()
{
    delete[] p;
    cout << "deconstructor called" << endl;
}

int &vectorInt::at(int index){
    assert(index >= 0 && index < size);
    return p[index];     
}

int vectorInt::get_size() const{
    return size;
}

void output(vectorInt &v){
    for(auto i = 0; i < v.size; i++)
        cout << v.p[i] << " " ;
    cout << endl;    
}

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

void test() {
    using namespace std;

    int n;
    cin >> n;
    
    vectorInt x1(n);
    for(auto i = 0; i < n; ++i)
        x1.at(i) = i*i;

    output(x1);

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

    output(x2);
    output(x3);

    x2.at(0) = 77;

    output(x2);
    output(x3);
}

int main() {
    test();
}

运行结果截图：

 

 

 

实验任务6

#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, 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
};

// 类Matrix的实现：待补足
// ×××
Matrix::Matrix(int n){
    lines = n;
    cols = n;
    p = new double[n*n];
}

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

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];
}

Matrix::~Matrix()
{
    delete[] p;
}

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

void Matrix::set(int i,int j,int value){
    int index = i * cols + j;
    p[index] = value;
}

double &Matrix::at(int i, int j)
{
    int index = i * cols + j;
    return p[index];
}

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 = 1; i <= lines; i++)
    {
        for (int j = 1; j <= cols; j++)
        {
            cout << p[(i-1) * cols + j - 1];
            if(j < cols)
               cout << "，";
        }
        cout << endl;
    }    
}

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

void test() {
    using namespace std;

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

    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();
}

运行结果截图：