实验四 类与数组，指针

实验任务5：

task5.hpp

#pragma once
#include<iostream>
#define MAXSIZE 10000

using namespace std;

class vectorInt {
public:
	//构造函数与析构函数
	vectorInt(int n);
	vectorInt(int n,int value);
	vectorInt(const vectorInt& x);
	~vectorInt();

	//成员函数
	int& at(int i);
	int get_size(vectorInt x);
	
private:
	int* data;
	int size;

	friend void output(const vectorInt& x);
};

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

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

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

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

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

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

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

　　task5.cpp

#include <iostream>
#include "vectorInt.h"

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();
}

　　运行测试结果：

实验任务6：

task6.hpp

#pragma once
#include <iostream>
#include <vector>
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
};

// 类Matrix的实现：待补足
Matrix::Matrix(int n) {
    p = new double[n * n];
    lines = n;
    cols = n;
}

Matrix::Matrix(int n, int m) {
    p = new double[n * m];
    lines = n;
    cols = m;
}

Matrix::Matrix(const Matrix& X) {
    lines = X.lines;
    cols = X.cols;
    p = new double[lines * cols];
    for (int i = 0; i < lines * cols; i++) {
        p[i] = X.p[i];
    }
}

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) {
    int index = 0;
    if (i == 0) {
        index = j;
    }
    else {
        index = (i - 1) * cols + j;
    }
    p[index] = value;
}

double Matrix::at(int i, int j) const {
    int index = 0;
    if (i == 0) {
        index =  j;
    }
    else {
        index = (i - 1) * cols + j;
    }
    
    double elem = p[index];
    return elem;
}

double& Matrix::at(int i, int j) {
    int index = 0;
    if (i == 0) {
        index = j;
    }
    else {
        index = (i - 1) * cols + j;
    }
    return p[index];
}

int Matrix::get_lines() const {
    return lines;
}

int Matrix::get_cols() const {
    return cols;
}

void Matrix::print() const {
    for (int i = 0; i < lines * cols; i++) {
        cout << p[i] <<" ";
        if ((i + 1) % cols == 0)
            cout << endl;
    }
}

　　task6.cpp

#include <iostream>
#include "Matrix.h"

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();
}

　　运行测试结果：

 修改测试数据后运行结果：