笔者用C语言开发了一个手工绘制电力系统一次接线图的键盘绘图程序，使用该程序绘制的一次接线图符合用户需求，效果良好。 -when program runs, a yellow color border to set the drawing area will apper on the screen, in the middle of drawing area will have brushes, when pressed sign of the "w" it becomes a brush

WPF 鼠标拖拽功能，自定义拖拽的跟随图形，不再是一个虚线的系统的小标志，而是具体所拖拽的对象的图形，比如拖一个button，后面跟随的就是一个button的形状。-WPF mouse drag and drop, drag the following custom graphics, broken system is no longer a small sign, but concrete by dragging a graphical object, such as dragging a b

matlab源码-符号函数，求解函数的极限 源程序-matlab source- sign function, solving the limit function can refer to the source code using the following