编写一个程序，实现两个矩阵相乘



需要第一个矩阵的列数与第二个矩阵的行数相同，结果是一个矩阵，且其行数与第一个矩阵的行数相同，与第二个矩阵的列数相同，结果矩阵中第i行/第j列的元素等于第一个矩阵的第i行的各元素与第二个矩阵第j列的各元素对应相乘之和。

-Write a program to multiply two matrices needed to achieve the first columns of a matrix of rows and the second the same number of matrix, the result is a matrix, and the number of rows with the first same number of rows of a matrix, and the second matrix the same number of columns, the results matrix in the i-row/j-column matrix of elements equal to the first line of the first i elements and the second j-column matrix corresponding to multiplying the sum of the elements.