实验四

task5:

//point.hpp

1 #pragma once
2 class point {
3 public:
4     point() {}
5     point(int xx) {x=xx; }
6     int return_x(){ return x; }
7 private:
8     int x;
9 };

//vectorInt.hpp

 1 #include<iostream>
 2 #include<string>
 3 #include"point.hpp"
 4 using namespace std;
 5 class vectorInt {
 6 public:
 7     point &at(int i);//获得下标为i的数组元素
 8     int get_size() { return n; }
 9     vectorInt(){};//默认构造函数
10     vectorInt(int nn);//带一个参数的构造函数
11     vectorInt(int nn, int pp);//带两个参数的构造函数
12     vectorInt(const vectorInt &v);//复制构造函数
13     ~vectorInt() { 
14         cout << "destructor called." << endl; 
15         delete[]p;//析构时需要释放资源 
16     }
17     friend void output(vectorInt &v);
18 private:
19     point *p;//指向数组首地址
20     int n;//数组长度
21 };
22 vectorInt::vectorInt(int nn) {
23     n = nn;
24     p = new point[nn];
25     cout << "constructor 1 called." << endl;
26 }//带一个参数的构造函数ok
27 vectorInt::vectorInt(int nn, int xx) {
28     n = nn;
29     p = new point[nn]; 
30     for (int j = 0; j < nn; j++) { 
31         p[j] = xx;
32     }
33     cout << "constructor 2 called." << endl;
34 }//带两个参数的构造函数ok
35 vectorInt::vectorInt(const vectorInt &v) {
36     n = v.n;
37     p = new point[n];
38     for (int j = 0; j < n; j++) {
39         p[j] = v.p[j];//先给一块新的内存空间再赋值即为深复制。
40     }
41     cout << "copy constructor called." << endl;
42 }//复制构造函数ok
43 void output(vectorInt&v) {
44     for (int i = 0; i < v.n; i++) {
45         cout<<(v.at(i).return_x())<< ",";//出现错误C3867    “point::return_x”:非标准语法请使用 "&" 来创建指向成员的指针    是因为return_x后忘记括号
46 
47     }
48     cout << "\b " << endl;
49 }
50 point &vectorInt::at(int i) {
51     return p[i];
52 }

//task5.cpp

 1 #include <iostream>
 2 #include<string>
 3 #include "vectorInt.hpp"
 4 void test() {
 5     using namespace std;
 6     int n;
 7     cin >> n;
 8 
 9     vectorInt x1(n);
10     for (auto i = 0; i < n; ++i)
11         x1.at(i) = i * i;
12     output(x1);
13     vectorInt x2(n, 42);
14     vectorInt x3(x2);
15     output(x2);
16     output(x3);
17     x2.at(0) = 77;
18     output(x2);
19     output(x3);
20 }
21 int main() {
22     test();
23 }

运行结果：

task6:

//Matrix.hpp

 1 #pragma once
 2 #include <iostream>
 3 using std::cout;
 4 using std::endl;
 5 class Matrix {
 6 public:
 7     Matrix(int n);                     // 构造函数，构造一个n*n的矩阵
 8     Matrix(int n, int m);              // 构造函数，构造一个n*m的矩阵
 9     Matrix(const Matrix &X);           // 复制构造函数，使用已有的矩阵X构造
10     ~Matrix();                         //析构函数
11     void set(const double *pvalue);     // 用pvalue指向的连续内存块数据按行为矩阵赋值
12     void set(int i, int j, int value); //设置矩阵第i行第j列元素值为value
13     double &at(int i, int j);          //返回矩阵第i行第j列元素的引用
14     double at(int i, int j) const;     // 返回矩阵第i行第j列元素的值
15     int get_lines() const;             //返回矩阵行数
16     int get_cols() const;              //返回矩列数
17     void print() const;                // 按行打印输出矩阵
18 private:
19     int lines; // 矩阵行数
20     int cols;  // 矩阵列数
21     double *p; // 指向存放矩阵数据的内存块的首地址
22 };
23 // 类Matrix的实现
24 Matrix::Matrix(int n) {
25     p = new double[n*n];
26     lines = n;
27     cols = n;
28 }
29 Matrix::Matrix(int n, int m) {
30     p = new double[n*m];
31     lines = n;
32     cols = m;
33 }
34 Matrix::Matrix(const Matrix&m) {
35     p = new double[m.lines*m.cols];
36     lines = m.lines;
37     cols = m.cols;
38     for (int i = 0; i < lines*cols; i++) {
39         p[i] = m.p[i];
40     }
41 }
42 Matrix::~Matrix(){}
43 void Matrix::set(const double * pvalue) {
44     for (int i = 0; i < lines*cols; i++) {
45         p[i] =pvalue[i];
46     }
47 }
48 void Matrix::set(int i, int j, int value) {
49     p[cols*i + j] = value;
50 }
51 double& Matrix::at(int i, int j) {
52     return p[cols*i+j];
53 }
54 double Matrix::at(int i, int j) const {
55     return p[cols*i + j ];
56 }
57 int Matrix::get_cols() const { return cols; }
58 int Matrix::get_lines() const { return lines; }
59 void Matrix::print() const {
60     for (int i = 0; i < lines; i++) {
61         for (int j = 0; j < cols; j++) {
62             cout << at(i,j) << ",";
63         }
64         cout <<"\b "<< endl;
65     }
66 }

//task6.cpp

 1 #include <iostream>
 2 #include "matrix.hpp"
 3 void test() {
 4     using namespace std;
 5     double x[] = { 1, 2, 3, 4, 5, 6 };
 6     Matrix m1(3, 2);    // 创建一个3×2的矩阵
 7     m1.set(x);          // 用一维数组x的值按行为矩阵m1赋值
 8     m1.print();         // 打印矩阵m1的值
 9     cout << "the first line is: " << endl;
10     cout << m1.at(0, 0) << " " << m1.at(0, 1) << endl;  // 输出矩阵m1第1行两个元素的值
11     cout << endl;
12 
13     Matrix m2(2, 3);
14     m2.set(x);
15     m2.print();
16     cout << "the first line is: " << endl;
17     cout << m2.at(0, 0) << " " << m2.at(0, 1) << " " << m2.at(0, 2) << endl;
18     cout << endl;
19 
20     Matrix m3(m2);      // 用矩阵m2构造新的矩阵m3
21     m3.set(0, 0, 999);  // 将矩阵m3第0行第0列元素值设为999
22     m3.print();
23 }
24 
25 int main() {
26     test();
27 }

运行结果：

改变数据后：