1 #pragma once
2 #include<iostream>
3 using namespace std;
4 class vectorInt{
5 public:
6 vectorInt(int n):size(n) {
7 cout << "construct 1 called"<<endl;
8 p = new int[n];
9 }
10 vectorInt(int n,int e):size(n) {
11 cout << "construct 2 called"<<endl;
12 p = new int[n];
13 for(int i = 0; i < size; i++) p[i] = e;}
14 vectorInt(vectorInt &obj): size{obj.size} {
15 cout << "copy constructor called" <<endl;
16 p = new int[size];
17 for(int i = 0;i < size; i++)
18 p[i] = obj.p[i];
19 }
20 ~vectorInt() {cout<< "destructor called" << endl;
21 delete[] p;}
22 int get_szie() const {return size;}
23 int &at(int n){ return p[n]; }
24
25 private:
26 int size;
27 int *p;
28
29 friend void output(vectorInt &x);
30 };
31
32 void output(vectorInt &x){
33 for(int i = 0; i < x.size; i++)
34 if(i!=x.size-1) cout << x.at(i) << ",";
35 else cout << x.at(i);
36 cout << endl;
37 }
vectorInt.hpp
1 #include <iostream>
2 #include "vectorInt.hpp"
3
4 void test() {
5 using namespace std;
6
7 int n;
8 cin >> n;
9
10 vectorInt x1(n);
11 for(auto i = 0; i < n; ++i)
12 x1.at(i) = i*i;
13
14 output(x1);
15
16 vectorInt x2(n, 42);
17 vectorInt x3(x2);
18
19 output(x2);
20 output(x3);
21
22 x2.at(0) = 77;
23
24 output(x2);
25 output(x3);
26 }
27
28 int main() {
29 test();
30 }
task5.cpp
1 #pragma once
2
3 #include <iostream>
4
5
6 using std::cout;
7 using std::endl;
8
9 class Matrix {
10 public:
11 Matrix(int n); // 构造函数，构造一个n*n的矩阵
12 Matrix(int n, int m); // 构造函数，构造一个n*m的矩阵
13 Matrix(const Matrix &X); // 复制构造函数，使用已有的矩阵X构造
14 ~Matrix(); //析构函数
15
16 void set(const double *pvalue); // 用pvalue指向的连续内存块数据按行为矩阵赋值
17 void set(int i, int j, int value); //设置矩阵第i行第j列元素值为value
18 double &at(int i, int j); //返回矩阵第i行第j列元素的引用
19 double at(int i, int j) const; // 返回矩阵第i行第j列元素的值
20 int get_lines() const; //返回矩阵行数
21 int get_cols() const; //返回矩列数
22 void print() const; // 按行打印输出矩阵
23
24 private:
25 int lines; // 矩阵行数
26 int cols; // 矩阵列数
27 double *p; // 指向存放矩阵数据的内存块的首地址
28 };
29
30 Matrix::Matrix(int n):lines{n},cols{n} {
31 p = new double[n*n];
32 }
33 Matrix::Matrix(int n, int m): lines{n},cols{m} {
34 p = new double[n*m];
35 }
36 Matrix::Matrix(const Matrix &X):lines{X.lines},cols{X.cols} {
37 p = new double[lines*cols];
38 for (auto i = 0; i < X.lines*X.cols; i++){
39 p[i] = X.p[i];
40 }
41 }
42 Matrix::~Matrix(){
43 delete[] p;
44 }
45 void Matrix::set(const double *pvalue){
46 int i = 0;
47 while(pvalue!=nullptr&&i < lines*cols){
48 p[i] = *pvalue;
49 i++;pvalue++;
50 }
51 }
52
53 void Matrix::set(int i, int j, int value){
54 p[i*cols+j] = value;
55 }
56
57 double &Matrix::at(int i, int j){
58 return p[i*cols+j];
59 }
60
61 double Matrix::at(int i, int j) const {
62 return p[i*cols+j];
63 }
64
65 int Matrix::get_lines() const{
66 return lines;
67 }
68
69 int Matrix::get_cols() const{
70 return cols;
71 }
72
73 void Matrix::print() const{
74 for(int i = 0; i < lines; i++){
75 for(int j = 0; j < cols; j++)
76 if (j!=cols-1) cout << p[i*cols+j] << ",";
77 else cout << p[i*cols+j];
78 cout << endl;
79 }
80 }
Matrix.hpp
1 #include <iostream>
2 #include "matrix.hpp"
3
4 void test() {
5 using namespace std;
6
7 double x[] = {165, 65, 55, 457, 73, 453, 54, 66, 64, 77, 79, 31};
8
9 Matrix m1(3, 4); // 创建一个3×2的矩阵
10 m1.set(x); // 用一维数组x的值按行为矩阵m1赋值
11 m1.print(); // 打印矩阵m1的值
12 cout << "the first line is: " << endl;
13 cout << m1.at(0, 0) << " " << m1.at(0, 1) << endl; // 输出矩阵m1第1行两个元素的值
14 cout << endl;
15
16 Matrix m2(4, 3);
17 m2.set(x);
18 m2.print();
19 cout << "the first line is: " << endl;
20 cout << m2.at(0, 0) << " " << m2.at(0, 1) << " " << m2.at(0, 2) << endl;
21 cout << endl;
22
23 Matrix m3(m2); // 用矩阵m2构造新的矩阵m3
24 m3.set(0, 0, 999); // 将矩阵m3第0行第0列元素值设为999
25 m3.print();
26 }
27
28 int main() {
29 test();
30 }
task6.cpp
实验总结
1.task5中输出函数，参数中用引用类型，否则会多次调用复制构造函数
2.用指针进行数组赋值时，主要最后回到初始位置
标签：const,Matrix,int,double,lines,cols,实验,数组,指针 From： https://www.cnblogs.com/xrzjjy/p/16856177.html