实验四

task5

vectorint.hpp

#pragma once

#include<iostream>
#include<cassert>

using namespace std;

class vectorint {
public:
    vectorint(){};
    vectorint(int n);
    vectorint(int n, int v);
    vectorint(const vectorint& x);
    ~vectorint() {
        cout << "destructor called." << endl;
        delete[]p;
    }
    int &at(int i);
    int get_size() { return size; }
private:
    int* p;
    int size;
    friend void output(vectorint &m);
};
vectorint::vectorint(int n) :size{ n } {
    cout << "constructor 1 called." << endl;
    p = new int[size];
}
vectorint::vectorint(int n, int v) :size{ n } {
    cout << "constructor 2 called." << endl;
    p = new int[size];
    for (int i = 0; i < n; i++) {
        p[i] = v;
    }
}
vectorint::vectorint(const vectorint& x) {
    cout << "copy constructor called." << endl;
    size = x.size;
    p = new int[size];
    for (int i = 0; i < size; i++) {
        p[i] = x.p[i];
    }
}
int& vectorint::at(int i) {
    assert(i >= 0 && i < size);
    return p[i];
}
void output(vectorint& v) {
    for (int i = 0; i < v.size; i++) {
        cout << v.p[i] << "," ;
    }
    cout << "\b " << endl;
}

task5.cpp

#include <iostream>
#include<string>
#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：

task6

Matrix.hpp

#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 
};

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* pvaule) {
    for (int i = 0; i < lines * cols; i++) {
        p[i] = pvaule[i];
    }
}
void Matrix::set(int i, int j, int vaule) {
    p[cols * i + j] = vaule;
}
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 <<at(i,j) << ",";
        }
        cout << "\b " << endl;
    }    
}

task6.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：