实验四 类与数组、指针

task5：

#pragma once

#include <iostream>
#include <cassert>
#include <string>

using namespace std;

class vectorInt {
    public:
    vectorInt(int n0);
    vectorInt(int n0, int value0);
    vectorInt(const vectorInt &v);
    ~vectorInt();
    
    int &at(int i);
    int get_size() { return n; };
    friend void output(vectorInt &v);
    
    private:
    int n;
    int *p;
};

vectorInt::vectorInt(int n0) : n{n0} {
    cout << "constructor 1 called" << endl;
    p = new int[n0];
}

vectorInt::vectorInt(int n0, int value0) : n{n0} {
    cout << "constructor 2 called" << endl;
    p = new int[n];
    for(auto i = 0;i <= n; i++)
        p[i] = value0;
}

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

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

int &vectorInt::at(int i) {
    assert(i >= 0 && i < n);
    return p[i];
} 

void output(vectorInt &v){
    for(auto i = 0; i < v.n; i++)
    cout << v.p[i] << " ";
    cout << endl;
}

#include <iostream>
#include "实验四task5_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();
}

 task6：

#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() = default;//构析函数 
        
        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);//设置第i行第j列元素值为value 
        double &at(int i, int j);//返回第i行第j列元素的引用 
        double at(int i, int j) const;//返回第i行第j列元素的值 
        int get_lines() const;//返回矩阵行数 
        int get_cols() const;//返回矩阵列数 
        void print();//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];
    for(auto i = 0; i < lines * cols; i++)
        p[i] = X.p[i];
} 

void Matrix::set(const double *pvalue) {
    for(auto 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() {
    for (auto i = 0; i < lines; i++)
    {
        for (auto j = 0; j < cols; j++)
           cout << p[i * cols + j] << ",";
        cout << "\b " << endl;
    }
}

#include <iostream>
#include "实验四task6_Matrix.hpp"

void test() {
    using namespace std;
    
    double x[] = {10, 11, 12, 13, 14, 15};
    
    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, 666);//将矩阵m3第0行第0列元素值设为999
    m3.print(); 
}

int main() {
    test();
}