矩阵相乘的小程序，第一个矩阵的每一行元素与第二个矩阵的每一列元素一一相乘，得到结果矩阵的每一个位置上的元素。-Matrix multiplication of small programs, the first element of each row and each column of the matrix elements of the second matrix is ​ ​ multiplied by one, to get a location on each el