程序的功能是：有五个学生，每个学生的数据包括学号、姓名(最长19字节)、三门课的成绩，从键盘输入五个学生的数据，并计算每个学生的平均成绩，最后显示最高平均分的学生的信息(包括学号，姓名，三门课的成绩，平均分数)。

-Functions of the program are: there are five students, each student data including student number, name (up to 19 bytes), three course results, five students from the keyboard input data, and calculate the average for each student results, and finally showed the highest average student information (including student number, name, three course results, the average score).