实验4 类与数组、指针

实验任务5: vectorInt.hpp:

#include<iostream>
#include <cassert>
using namespace std; 
class vectorInt{
    public:
        vectorInt(int n);
        vectorInt(int n, int value); 
        ~vectorInt();
        vectorInt(const vectorInt &v);
        int &at(int index);
        int get_size();
        friend void output(vectorInt &v);
    
    private:
        int size;
        int *p;
};

vectorInt::vectorInt(int n):size{n}{
    cout<<"constructor 1 called."<<endl;
    p=new int[n];
}

vectorInt::vectorInt(int n, int value):size{n}{
    cout<<"constructor 2 called."<<endl;
    p=new int[size];
    for(auto i=0;i<size;i++)
        p[i]=value;
}

vectorInt::~vectorInt(){
    cout<<"destructor called."<<endl;
    delete[] p;
}

vectorInt::vectorInt(const vectorInt &v):size{v.size}{
    cout<<"copy constructor called."<<endl;
    p=new int[size];
    for(auto i=0;i<size;i++)
        p[i]=v.p[i];
}

int &vectorInt::at(int index){
    assert(index>=0&&index<size);
        return p[index];
}

int vectorInt::get_size(){
    return size;
}

void output(vectorInt &v){
    for(auto i=0;i<v.size;i++)
        cout<<v.p[i]<<", ";
        cout<<"\b\b \n";
}

task 5:

#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();
}

运行结果：

#pragma once

#include <iostream>
#include <cassert>

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(auto i=0;i<lines*cols;i++)
        p[i]=X.p[i];
}

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

void Matrix::set(const double *pvalue){
    for(auto 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){
    assert(i >= 0 && i < lines && j >= 0 && j < cols);
    return p[i*cols+j];
}

double Matrix::at(int i, int j) const{
    assert(i >= 0 && i < lines && j >= 0 && j < cols);
    return p[i*cols+j];    
}

int Matrix::get_lines() const{
    return lines;
}

int Matrix::get_cols() const{
    return cols;
}

void Matrix::print() const{
    for(auto i=0;i<lines;i++){
        for(auto j=0;j<cols;j++)
        cout<<p[i*cols+j]<<", ";
    cout<<"\b\b \n";
    }
}

task 6:

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

void test() {
    using namespace std;

    double x[] = {1, 2, 3, 4, 5, 6};

    Matrix m1(3, 2);    
    m1.set(x);         
    m1.print();         
    cout << "the first line is: " << endl;
    cout << m1.at(0, 0) << " " << m1.at(0, 1) << endl; 
    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);     
    m3.set(0, 0, 999);  
    m3.print();
}

int main() {
    test();
}

运行结果：