#include <opencv2/opencv.hpp>
#include <iostream>
using namespace std;
using namespace cv;

void PrintMat( Mat &_m)
{

    Mat m = Mat_<float>( _m );
    for ( int k1=0; k1<m.rows; k1++ )
    {
        for ( int k2=0; k2<m.cols; k2++ )
        {
            cout << m.at<float
 
>(k1,k2) << "    ";
        }
        cout << endl;
    }
    cout << "m.rows： " << _m.rows << endl << "m.cols： " << _m.cols << endl;
}

int main()
{   

        Mat m = Mat::zeros(2,2,CV_32F);

        m.at<float>(0,0) = 1;
        m.at<float
 
>(0,1) = 2;
        m.at<float>(1,0) = 3;
        m.at<float>(1,1) = 4;

        m.reshape(0, 1);    //沒有賦值給m，只是噹噹reshape的話，m的行列都不會顯示出來有改變
        cout << "m:" << endl;
        PrintMat(m);
        cout << endl;

        cout << "m.reshape(0, 1):" << endl;
        m = m.reshape(0
 
, 1);//賦值給m的後，m的行列發生改變
        cout << "m:" << endl;
        PrintMat(m) ;
        cout << endl;

        cout << "m.reshape(0, 4):" << endl;
        Mat m1 = m.reshape(0, 4);   //也可以賦值給新的mat
        cout << "m1:" << endl;
        PrintMat(m1);
        cout << endl;

        return 0;

}

執行結果：