8.2 (C++)

这题比较难，可以不做，作业截止后将会删掉。

Design a class Sparse that implements interface Matrix: Sparse should has the following public object functions in addition:

A constructor Sparse(int rows, int column), which initializes all elements in the matrix to 0's.
A copy constructor Sparse(Matrix & matrix2).
A destructor.
A print function which prints each entry of non-zero element in a single line. Only the triples for the non-zero elements are printed. The triples are ordered first by their row indexes, then by their column indexes.
Hint:
A sparse matrix is a matrix where most elements are 0's. To represent a sparse matrix efficiently, we only need to store its non-zero elements. Each non-zero element is represented using a 3-tuple (row, col, value), where row and col are the row-number and column-number of the element, and value is the value of the element. The class Entry below is the class for this 3-tuple.
An iterator is a class to visit all of the elements in a container. In this exercise, you need to implement an iterator to inspect all non-zero elements in your Sparse matrix. For more about iterator, please refer to my lecture note (lectureNote6-8.pdf).
EXAMPLE INPUT
1000000 1000000
1 1 10
1000000 1000000 20
1 1000000 30
1000000 1 40
EXAMPLE OUTPUT
(1,1,10)
(1000000,1000000,20)

(1,1,10)
(1000000,1000000,20)

(1,1,10)
(1,1000000,30)
(1000000,1,40)
(1000000,1000000,20)

(1,1,10)
(1,1000000,30)
(1000000,1,40)
(1000000,1000000,20)
主程序 (不能修改)

class Entry
{
public:
    int row;
    int column;
    double value;
};
    
class Iterator
{
public:
    virtual bool hasNext() const = 0;
    virtual const Entry & next() = 0;
};
    
class Matrix
{
public:
    virtual Iterator * iterator() const  = 0; //增加了const
    virtual int size(int dimension) const = 0;
    virtual void set(int row, int column, double value) = 0;
    virtual double get(int row, int column) const = 0;
    virtual void print() = 0;
    virtual Matrix & operator = (const Matrix & matrix2) = 0;
};

#include "source.cpp"

#include <iostream>
using namespace std;

void printMatrix(Matrix & matrix) {
    matrix.print();
}

// 新增
void printMatrix2(const Matrix & matrix) {
    Iterator * it = matrix.iterator();
    while (it->hasNext()) {
        Entry entry = it->next();
        cout << "(" << entry.row << "," << entry.column <<
            "," << entry.value << ")" << endl;
    }
    delete it;
}

int main() {
    int rows;
    int columns;
    cin >> rows >> columns;
    
    int row1;
    int column1;
    double value1;
    cin >> row1 >> column1 >> value1;
    
    int row2;
    int column2;
    double value2;
    cin >> row2 >> column2 >> value2;
    
    int row3;
    int column3;
    double value3;
    cin >> row3 >> column3 >> value3;
    
    int row4;
    int column4;
    double value4;
    cin >> row4 >> column4 >> value4;
    
    
    Sparse sparse1(rows, columns);
    Matrix & matrix1 = sparse1;
    matrix1.set(row1, column1, value1);
    matrix1.set(row2, column2, value2);
    matrix1.print();
    cout << endl;
    
    Sparse sparse2(sparse1);
    Matrix & matrix2 = sparse2;
    matrix2.print();
    cout << endl;
    
    matrix2.set(row3, column3, value3);
    matrix2.set(row4, column4, value4);
    matrix1 = matrix2;
    matrix1.print();
    cout << endl;
    
    // 新增
    printMatrix2(matrix1);
    
}

我的答案