对称矩阵相乘：2.　　A和B是两个n×n阶的对称矩阵，以行为主序输入对称矩阵的下三角元素，压缩存储存入一维数组A和B，编写一个算法计算对称矩阵A和B的乘积，结果存入二维数组C。-Symmetric matrices: 2. A and B are two n × n symmetric band matrix, in order to conduct the main sequence of input symmetric matrix elements of lower triangular, compressed storage into one-dimensional array A and B, the preparation of a symmetric matrix algorithm the product of A and B, the results of two-dimensional array into C.