用友元函數的定義，定義壹個3*3的矩陣類和3唯向量，兩個相乘做到類的成員函數中。 C++編程

int type;

int step;

int* refcount; // for internal use only

union {

uchar* ptr;

short* s;

int* i;

float* fl;

double* db;

} data;

union {

int rows;

int height;

};

union {

int cols;

int width;

};

} CvMat;