实验四

task5

hpp

#pragma once
#include<iostream>
using namespace std;

class vectorInt {
public:
    vectorInt(int n);
    vectorInt(int n, int value);
    vectorInt(vectorInt& x);
    ~vectorInt();
    int& at(int i);
    int get_size() { return size; }

private:
    int size;
    int* y;

    friend void output(vectorInt &x);
};

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

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

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

vectorInt::~vectorInt() {
    cout << "destructor called." << endl;
    delete[]y;
}

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

void output(vectorInt& x) {
    for (int i = 0; i < x.size; i++) {
        cout << x.y[i] << " ";
    }
    cout << endl;
}

cpp

#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：

task5

hpp

#pragma once
#include <iostream>
#include<iomanip>

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; i++) {
        for (int j = 0; j < cols; j++) {
            p[i * cols + j] = x.p[i * cols + 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) {
    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 (int i = 0; i < lines; i++) {
        for (int j = 0; j < cols; j++) {
            cout << setw(5) << left << p[i * cols + j];
        }
      cout << endl;
    }
}

cpp

#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