实验4 类与数组、指针

实验5：
#include<iostream>
using std::cout;
using std::endl;
using std::cin;

class vectorInt {
public:
    vectorInt(int n);
    vectorInt(int n, int m);
    ~vectorInt() { cout << "destructor called" << endl; delete[] p; }
    vectorInt(const vectorInt& p);
    int &at(int index);  
    int get_size()const;
    friend void output(vectorInt& p1);
private:
    int size;
    static int number ;//number用于记录调用构造函数的次数
    int* p;
};
vectorInt::vectorInt(int n) :size{n} {
    cout << "constructor " << number << " called" << endl; 
    p = new int[n];
    number = number + 1;
}
vectorInt::vectorInt(int n, int m) :size{n} {
    cout << "constructor " << number << " called" << endl;
    p = new int[n];
    for (int i = 0; i < n; i++)
        p[i] = m;
    number = number + 1;
}
vectorInt::vectorInt(const vectorInt& vp) :size{vp.size} {
    cout << "copy constructor called"<<endl;
    p = new int[size];
    for (auto i = 0; i < size; i++)
        p[i] = vp.p[i];
}
int &vectorInt::at(int index) {
    if (index >= 0 && index < size)
        return p[index];
}
int vectorInt::get_size()const {
    return size;
}

void output(vectorInt &p1) {
    for (int i = 0; i < p1.size; i++)
        cout << p1.p[i]<<", ";
    cout << endl;
}
int vectorInt::number = 1;

测试代码：

#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6：

#include<iostream>
using std::cout;
using std::endl;
class Matrix {
public:
	Matrix(int n);
	Matrix(int n, int m);
	Matrix(const Matrix& x);
	~Matrix();
	void set(const double* pvalue);
	void set(int i, int j, int value);
	double& at(int i, int j);
	double at(int i, int j)const;
	int get_lines()const;
	int get_cols()const;
	void print()const;
private:
	int lines;
	int cols;
	double* p;
};

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 - 1; j++)
	    cout << p[i * cols + j] << ", ";
	  cout << p[i * cols + cols -1] << endl;
	}
}

测试代码：

#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();
}

　　

更换一组数据：

#include <iostream>
#include "matrix.hpp"

void test()
{
    using namespace std;

    double x[] = { 51, 28, 32, 45, 55, 76 };

    Matrix m1(2, 3); // 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) << " " << m1.at(0,2)<<endl; // 输出矩阵m1第1行两个元素的值
    cout << endl;

    Matrix m2(3, 2);
    m2.set(x);
    m2.print();
    cout << "the double line is: " << endl;
    cout << m2.at(2, 0) << " " << m2.at(2, 1) << 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();
}