学习笔记：矩阵的基本运算的实现

Posted 2020-10-05 pprp

2017-09-05 21:33:33

writer：pprp

昨天开始就上课了，没有整天整天的时间去编代码了，充分抓住每天晚上的时间吧，

今天下午预习了一下线性代数中矩阵最基本的运算，今晚就打算实现一下基本的功能

矩阵加法，矩阵减法，矩阵乘法，矩阵转置

代码如下：

/*
@theme:矩阵类的实现
@writer:pprp
@begin:20:48
@end:21:30
@declare:注意行还有列的赋值
@date:2017/9/5
*/

#include <bits/stdc++.h>

using namespace std;
#define N 100
int MAXN, n, mod;

class Matrix
{
public:
    int data[N][N];
    int col, row;
    void Init()
    {
        memset(data,0,sizeof(data));
    }
    //test:ok
    void MatrixMultiply(const Matrix& A, const Matrix & B)
    {
        if(A.col != B.row)
        {
            cout << "A.col != B.row" << endl;
            return ;
        }
        Init();
        row = A.row, col = B.col; //更新乘法得到的矩阵的行和列
        for(int i = 0 ; i < A.row ; i++)
        {
            for(int j = 0 ; j < B.col; j++)
            {
                data[i][j] = 0;
                for(int k = 0 ; k < A.col; k++)
                {
                    data[i][j] += A.data[i][k] * B.data[k][j];
                }
            }
        }
    }
    //test:ok
    void MatrixAdd(const Matrix & A,const Matrix & B)
    {
        if(A.row != B.row || A.col != B.col)
        {
            cout << "can‘t add these two Matrix!" << endl;
            return ;
        }
        Init();
        row = B.row, col = B.col;
        for(int i = 0 ; i < row; i++)
        {
            for(int j = 0; j < col; j++)
            {
                data[i][j] = A.data[i][j] + B.data[i][j];
            }
        }
    }
    //test:ok
    void MatrixSub(const Matrix & A, const Matrix & B)
    {
        if(A.row != B.row || A.col != B.row)
        {
            cout << "can‘t sub the two Matrix!" << endl;
            return;
        }
        row = B.row, col = A.col;
        for(int i = 0 ; i < row; i++)
        {
            for(int j = 0 ; j < col; j++)
            {
                data[i][j] = A.data[i][j] - B.data[i][j];
            }
        }
    }
    //test:ok
    void MatrixReverse(const Matrix & A)
    {
        row = A.col, col = A.row;
        Init();
        for(int i = 0 ; i < row; i++)
        {
            for(int j = 0 ; j < col; j++)
            {
                data[i][j] = A.data[j][i];
            }
        }
    }
    //test:ok
    void OutputMatrix()const
    {
        for(int i = 0 ; i < row; i++)
        {
            for(int j = 0 ; j < col; j++)
            {
                cout << data[i][j] << " ";
            }
            cout << endl;
        }
    }
    //test:ok
    void SetRC(int r,int c)
    {
        row = r, col = c;
    }
    //test:ok
    void InputMatrix()
    {
        Init();
        for(int i = 0 ; i < row; i++)
        {
            for(int j = 0; j < col; j++)
            {
                cin >> data[i][j];
            }
        }
    }
};



int main()
{
    freopen("in.txt","r",stdin);
    Matrix mx1, mx2, ans;
    //第一个矩阵
    cout << "input the row and the col of the first Matrix" << endl;
    int row, col;
    cin >> row >> col;
    mx1.SetRC(row,col);
    cout << "input the first Matrix" << endl;
    mx1.InputMatrix();
    mx1.OutputMatrix();

    //第二个矩阵
    cout << "input the row and the col of the second Matrix" << endl;
    cin >> row >> col;
    mx2.SetRC(row,col);
    cout << "input the second Matrix" << endl;
    mx2.InputMatrix();
    mx2.OutputMatrix();
/*
    cout << "add:" << endl;
    ans.MatrixAdd(mx1,mx2);
    ans.OutputMatrix();

    cout << "sub:" << endl;
    ans.MatrixSub(mx1,mx2);
    ans.OutputMatrix();

    cout << "reverse:" << endl;
    ans.MatrixReverse(mx2);
    ans.OutputMatrix();

*/
    cout << "multiply: " << endl;
    ans.MatrixMultiply(mx1,mx2);
    ans.OutputMatrix();
    return 0;
}

/*
test:

2 3
1 2 3
4 5 6
3 3
1 -1 2
0 1 1
-1 1 -1
*/