task4: 模拟实验任务2，不使用标准库模板类vector，自己动手设计并实现一个动态的整型数组类Vector_int
vector_int.hpp
1 #ifndef VECTOR_INT_HPP
2 #define VECTOR_INT_HPP
3 #include<iostream>
4 #include<cassert>
5 using namespace std;
6 class Vector_int
7 {
8 private:
9 int *p;
10 int size;
11 public:
12 Vector_int(int n,int a);
13 Vector_int(const Vector_int &a);
14 int &at(int index);
15 ~Vector_int();
16 friend void print(const Vector_int a);
17 };
18
19 Vector_int::Vector_int(int n,int a=0):size(n)
20 {
21 p=new int[size]();
22 for (int i = 0; i < size; i++)
23 *(p+i)=a;
24 cout<<"Constructor called."<<endl;
25 }
26 Vector_int::Vector_int(const Vector_int &a):size(a.size)
27 {
28 p=new int[size]();
29 for (int i = 0; i < size; i++)
30 *(p+i)=*(a.p+i);
31 cout<<"Copy Constructor called."<<endl;
32 }
33 Vector_int::~Vector_int()
34 {
35 delete []p;
36 cout<<"Destructor called."<<endl;
37 }
38 int &Vector_int::at(int index)
39 {
40 assert(index>=0&&index<size);
41 return p[index];
42 }
43 #endif
task4.cpp
1 #include<iostream>
2 #include"vector_int.hpp"
3 void print(const Vector_int a)
4 {
5 for (int i = 0; i < a.size; i++)
6 cout<<a.p[i]<<ends;
7 cout<<endl;
8 }
9
10 int main()
11 {
12 int n;
13 cout<<"请输入数组大小：";
14 cin>>n;
15 Vector_int x(n); // 创建一个动态大小的int型数组对象x，向系统申请n个int型数据项空间
16 Vector_int y(n, 5); // 创建一个动态大小的int型数组对象x，向系统申请n个int型数据项空间, 初始值均为6
17 Vector_int z(x); // 用已经存在的对象x构造新的对象y
18 z.at(0) = 999; // 通过at()方法访问对象y中索引为0的数据项
19 print(x);
20 print(y);
21 print(z);
22 }
task5：实现一个动态矩阵类Matrix
Matrix.cpp
1 #ifndef MATRIX_HPP
2 #define MATRIX_HPP
3 #include <iostream>
4 #include <cassert>
5 class Matrix
6 {
7 public:
8 Matrix(int n);
9 Matrix(int n, int m);
10 Matrix(const Matrix &X);
11 ~Matrix();
12
13 void set(const double *pvalue);
14 void set(int i, int j, int value);
15 double &at(int i, int j);
16 double at(int i, int j) const;
17 int get_lines() const;
18 int get_cols() const;
19 void print() const;
20
21 private:
22 int lines;
23 int cols;
24 double *p;
25 };
26
27 Matrix::Matrix(int n):lines(n),cols(n)
28 {
29 p=new double[lines*cols];
30 }
31
32 Matrix::Matrix(int n,int m):lines(n),cols(m)
33 {
34 p=new double[lines*cols];
35 }
36
37 Matrix::Matrix(const Matrix &X):lines(X.lines),cols(X.cols)
38 {
39 p=new double[lines*cols];
40 for (int i = 0; i < lines*cols; i++)
41 p[i]=X.p[i];
42 }
43
44 Matrix::~Matrix()
45 {
46 std::cout<<"Destructor called"<<std::endl;
47 delete []p;
48 }
49
50 void Matrix::set(const double *pvalue)
51 {
52 for (int i = 0; i < lines*cols; i++)
53 p[i]=pvalue[i];
54 }
55 void Matrix::set(int i,int j,int value)
56 {
57 p[i*cols+j]=value;
58 }
59
60 double &Matrix::at(int i,int j)
61 {
62 assert(i>=0&&i<lines&&j>=0&&j<cols);
63 return p[i*cols+j];
64 }
65
66 double Matrix::at(int i,int j)const
67 {
68 assert(i>=0&&i<lines&&j>=0&&j<cols);
69 return p[i*cols+j];
70 }
71
72 int Matrix::get_lines()const
73 {
74 return lines;
75 }
76
77 int Matrix::get_cols()const
78 {
79 return cols;
80 }
81
82 void Matrix::print()const
83 {
84 for (int i = 0; i < lines; i++)
85 {
86 for (int j = 0; j < cols; j++)
87 std::cout<<p[i*cols+j]<<" ";
88 std::cout<<std::endl;
89 }
90 }
91 #endif
task5.cpp
1 #include<iostream>
2 #include"Matrix.hpp"
3 int main(){
4 using namespace std;
5
6 double x[] = {3, 6, 3, 4, 5, 6};
7
8 Matrix m1(3, 2); // 创建一个3×2的矩阵
9 m1.set(x); // 用一维数组x的值按行为矩阵m1赋值
10 m1.print(); // 打印矩阵m1的值
11 cout << "the first line is: " << endl;
12 cout << m1.at(0, 0) << " " << m1.at(0, 1) << endl;
13 cout << endl;
14
15 Matrix m2(2, 3);
16 m2.set(x);
17 m2.print();
18 cout << "the first line is: " << endl;
19 cout << m2.at(0, 0) << " " << m2.at(0, 1) << " " << m2.at(0, 2) << endl;
20 cout << endl;
21
22 Matrix m3(m2);
23 m3.set(1, 1, 888);
24 m3.print();
25 return 0;
26 }
总结：
1.学到了动态创建数组的方法，即new和delete的使用
2.学习到了标准c++头文件cassert中assert的使用