实验4 类与数组、指针

实验任务5

#pragma once
#include<iostream>

using std::cout;
using std::endl;

class vectorInt {
public:
    //构造函数和析构函数
    vectorInt(int n);
    vectorInt(int n, int value);
    vectorInt(const vectorInt& X);
    ~vectorInt();  //~vectorInt()=default;  默认合成的析构函数 

    //其它成员函数
    int& at(int i);
    int get_size();

    //友元函数
    friend void output(const vectorInt& X);

private:
    int size;
    int* p;
};

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

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

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

vectorInt::~vectorInt() {
    cout << "destructor called.\n";
    delete[]p;
}

int& vectorInt::at(int i) {
    return p[i];
}

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

void output(const vectorInt& X) {
    for (auto i = 0; i < X.size; i++)
        cout << X.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();
}

实验测试截图：

 

 

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：

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[X.lines * X.cols];
    for (auto i = 0; i < X.lines * X.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 * 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 {
    for (auto i = 0; i < lines * cols; i++) {
        cout << p[i] << " ";
        if ((i+1) % cols == 0) cout << '\n';
    }
}

#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();
}

测试截图：