2.从键盘输入10个整形数据，将这10个数据写到c盘的test2.txt中，然后关闭文件。接着再打开文件读出这10个数据求平均值，并将平均值写入test2.txt中。-Enter shaping data from the keyboard 10, the data is written to these 10 test2.txt c drive, and then close the file. And then open the file to read the data out of this 10 average, and the average value of the write test2.txt.