实验3 类和对象II

实验任务4

"vector_int.hpp"

#include <iostream>
#include <cassert>
using namespace std;

class Vector_int {
public:
    Vector_int(int n);
    Vector_int(int n, int value);
    Vector_int(const Vector_int &x);
    ~Vector_int();
    int& at(int index);
    void print();
    
private:
    int size;
    int* m;
}; 

Vector_int::Vector_int(int n): size(n) {
    m = new int[size];
    for(int i = 0; i < size; i++)
        m[i] = 0;
    cout << "The array has been created." << endl;
} 

Vector_int::Vector_int(int n, int value): size(n) {
    m = new int[size];
    for(int i = 0; i < size; i++)
        m[i] = value;
    cout << "The array has been created and every data item in it has been initialized as " << value << endl;
} 

Vector_int::Vector_int(const Vector_int &x): size(x.size) {
    m = new int[size];
    for(int i = 0; i < size; i++)
        m[i] = x.m[i];
    cout << "Copy constructor called." << endl;
}

Vector_int::~Vector_int() {
    delete[] m;
    cout << "Destructor called." << endl;
}

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

void Vector_int::print() {
    for (int i = 0; i < size; i++)
        cout << m[i] << " ";
    cout << endl;
}

"task4.cpp"

#include <vector_int.hpp>
#include <iostream>
using namespace std;

int main() {
    Vector_int arr1(8);
    Vector_int arr2(10, 7);
    Vector_int arr3(arr1);
    arr2.at(6) = 4;
    
    cout << "arr1:" << endl;
    arr1.print();
    cout << "arr2:" << endl;
    arr2.print();
    cout << "arr3:" << endl;
    arr3.print();
    
    return 0; 
}

运行结果

 实验任务5

"Matrix.hpp"

#include <iostream>
using namespace std;
 
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
};

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 (int i = 0; i < lines * cols; i++)
         p[i] = X.p[i]; 
}

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

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

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

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

double Matrix::at(int i, int j) const {
    return p[i * lines + 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;
    }
}

"task5.cpp"

#include <Matrix.hpp>
#include <iostream>
using namespace std;

int main() {
    double x[] = {3, 1, 4, 1, 5, 9};
    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, 65); // 将矩阵m3第0行第0列元素值设为65
    m3.print();
}

运行结果