实验四

task5:

vectorInt.hpp:

#pragma once 
#include<bits/stdc++.h>
#include<iomanip>
using namespace std;

class vectorInt{
    public:
        vectorInt(int num):size{num}{
            p=new int[size]; 
            cout<<"constructor 1 called."<<endl;
        }
        
        vectorInt(int num,int value):size{num}{
            p=new int[size];
            for(int i=0;i<num;i++){
                p[i]=value;
            }
            cout<<"constructor 2 called."<<endl;
        }
        
        vectorInt(const vectorInt &obj):size{obj.size}{
            p=new int[size];
            for(int i=0;i<size;i++){
                p[i]=obj.p[i];
            }
            cout<<"copy constructor called."<<endl;
        }
        
        ~vectorInt(){
            delete[] p;
            cout<<"destructor called."<<endl;
        }
        
        int get_size(){
            return size;
        }
        
        int &at(int index){
            assert(index>=0&&index<size);
            return p[index];
        }
        
        friend void output(vectorInt &obj){
            for(int i=0;i<obj.size-1;i++){
                cout<<setw(3)<<left<<obj.p[i];
            }
            cout<<obj.p[obj.size]<<endl;
        }
         
    private:
        int *p;
        int size;
}; 

task5.cpp:

#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();
}

task5.cpp运行结果截图

 

 task6：

Matrix.hpp：

#pragma once

#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];
    for(int i=0;i<n;i++){
        p[i]=new double[n];
    } 
}
 
Matrix::Matrix(int n,int m):lines{n},cols{m}{
    p=new double*[n];
    for(int i=0;i<n;i++){
        p[i]=new double[m];
    }
}

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

Matrix::~Matrix(){
    delete[] p;
}

void Matrix::set(const double *pvalue){
    int n=0;
    for(int i=0;i<lines;i++){
        for(int j=0;j<cols;j++){
            p[i][j]=pvalue[n++];
        }
    }
}

void Matrix::set(int i,int j,int value){
    p[i][j]=value;
}

double &Matrix::at(int i,int j){
    return p[i][j];
}

double Matrix::at(int i,int j)const{
    return p[i][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;j++){
            cout<<p[i][j]<<" "; 
        }
        cout<<endl;
    }
}

task6.cpp：

#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();
}

task6.cpp运行结果截图：