C++矩阵模板类的实现

你的名字 2022-02-25 10:34 253阅读 0赞

/*************************************************************
    **
    ** Matrix template class.
    **
    ** By shaoguang @ 2019-04-01.
    **
    *************************************************************/
    
    #ifndef MATRIX_H
    #define MATRIX_H
    
    #include <vector>
    
    /**
     * https://en.cppreference.com/w/cpp/types/size_t/
     * When indexing C++ containers, such as std::string, std::vector, etc, 
     * the appropriate type is the member typedef size_type provided by such containers. 
     * It is usually defined as a synonym for std::size_t.
     **/
    
    template <class T>
    class Matrix
    {
    public:
    	Matrix(int rows, int cols) : _array(rows)
    	{
    		for (auto & thisRow : _array)
    			thisRow.resize(cols);
    	}
    	// copy constructor.
    	Matrix(std::vector<std::vector<T>> src) : _array{ src }
    	{}
    	// move constructor.
    	Matrix(std::vector<std::vector<T>> && src) : _array{ std::move(src) }
    	{}
    
    	// overload operator [].
    	const std::vector<T> & operator[](std::size_t row) const
    	{
    		return _array[row];
    	}
    	std::vector<T> & operator[](std::size_t row)
    	{
    		return _array[row];
    	}
    
    	// Rows of matrix.
    	std::size_t rows() const
    	{
    		return _array.size();
    	}
    
    	// Cols of matrix.
    	std::size_t cols() const
    	{
    		return rows() ? _array[0].size() : 0;
    	}
    
    private:
    	std::vector<std::vector<T>> _array;
    };
    
    #endif // MATRIX_H

示例程序:

/*************************************************************
    **
    ** Matrix template class demo.
    **
    ** By shaoguang @ 2019-04-01.
    **
    *************************************************************/
    
    #include "matrix.h"
    #include <iostream>
    using namespace std;
    #include <cstdlib>
    #include <cstdio>
    
    std::vector<int> row1{ 1, 2, 3, 4, 5 };
    std::vector<int> row2{ 2, 3, 4, 5, 6 };
    std::vector<int> row3{ 3, 4, 5, 6, 7 };
    std::vector<std::vector<int>> src{ row1, row2, row3 };
    
    int main()
    {
    	Matrix<int> matrix(src);
    
    	for (std::size_t i = 0; i < matrix.rows(); ++i)
    	{
    		printf("row_%d : ", i);
    		for (std::size_t j = 0; j < matrix.cols(); ++j)
    			cout << matrix[i][j];
    		cout << endl;
    	}
    
    	system("pause");
    	return 0;
    }

MSVC15测试结果:

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L1dVOTc5Nw_size_16_color_FFFFFF_t_70][]

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L1dVOTc5Nw_size_16_color_FFFFFF_t_70]: /images/20220225/c973aa93e708406dab60c27dcbe4c9b2.png