里面有五个程序，分别是计算两个日期天数的c++文件；计算矩阵乘法的C文件；一个卫生管理系统的c文件；一个简单图形java文件；一个java象棋文件-Inside there are five procedures, namely, the number of days the two dates calculated c++ file　computing matrix multiplication of the C file　a health management system, c files　a simple graphical java files　a java chess file