数据结构上机实验——矩阵相乘。可实现输入两稀疏矩阵，用户自定义选择矩阵相乘模式并显示相乘结果。简明、易懂、C++自编版。-Data structure on experiments- matrix multiplication. Enter the two sparse matrices can be realized, user-defined selection matrix multiplication mode and display the multiplication result. Concise, easy to understand, C++ self-compiled version.