包含两个文件，一个是.BGI文件，是图形化得驱动，没有它该C语言程序无法正常显示，另外一个是源程序，本程序功能为图形化的计算器-Contains two files, one. BGI document is too graphic drivers, without which the C language program can not display properly, the other is the source, this program features for the graphi