实验3 类和对象Ⅱ

vector_int.hpp

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

class vector_int{
private:
    int n;
    int *x;
public:
    vector_int(int size_n);
    vector_int(int size_n, int x0);
    vector_int(const vector_int &p);
    ~vector_int();
    int &at(int index);
};

vector_int::vector_int(int size_n) : n(size_n) {
    cout << "constructor called." << endl;
    x = new int[n];
}

vector_int::vector_int(int size_n, int x0) : n(size_n) {
    cout << "constructor called and  been initialized" << endl;
    x = new int[n];
    for (int i = 0; i < n; i++) {
        x[i] = x0;
    }
}

vector_int::vector_int(const vector_int &p):n(p.n) {
    cout << "copy constructor called" << endl;
    x = new int[n];
    for (int i = 0; i < n; i++) {
        x[i] = p.x[i];
    }
}

vector_int::~vector_int() {
    cout << "delating ..." << endl;
    delete[] x;
}

int &vector_int::at(int index) {
    assert(index >= 0 && index < n);
    return x[index];
}

#endif

task4.hpp

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

int main() {
    int m, n;
    std::cin >> n >> m;
    vector_int x1(n);
    vector_int x2(n, m);
    for (int i = 0; i < n; i++) {
        std::cout << x2.at(i) << " ";
    }
    std::cout << std::endl;
    vector_int x3(x2);
    for (int i = 0; i < n; i++) {
        std::cout << x3.at(i) << " ";
    }
    std::cout << std::endl;
    x2.at(0) = 999;
    for (int i = 0; i < n; i++) {
        std::cout << x2.at(i) << " ";
    }
    std::cout << std::endl;
}

 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, 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];
    int q = 0;
    for (int i = 0; i < lines; i++) {
        for (int j = 0; j < cols; j++) {
            p[q++] = X.at(i, j);
        }
    }
}

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 * cols + j] = value;
}

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

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++) {
            std::cout << p[i * cols + j] << " ";
        }
        std::cout << std::endl;
    }
}

#endif

task5.hpp

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

int main()
{
    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;
    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, 999);
    m3.print();
}