利用c开发gis的基本功能，包括基本图形的绘制及对常用格式的调用-Use c the development of the basic functions of gis, including basic drawing and graphics format commonly used to call

此程序主要是介绍画直线的两种方法，其中包括中点画线和梁友栋画线-The procedure is to introduce the two methods of drawing a straight line, which includes the dotted line and draw a line Liangyou Dong