markdown画流程图

参看链接：
@ Subson https://blog.csdn.net/zhaodedong/article/details/47671679
@ 木东居士 https://blog.csdn.net/Subson/article/details/75126945

画流程图
常用类型：
start 开始
end 结束
operation 操作
subroutine 子程序
condition 条件判断
inputoutput 输出
画图整体代码块与java类似，flow表示下面的块是流程图，格式如下：

```flow
代码区
​```

先定义各类型模块 名字=>类型: 描述，再定义连线 mode1->mode2 。
example1

st=>start: Start
e=>end: End
op=>operation: My Operation
cond=>condition: Yes or No?

st->op->cond
cond(yes)->e
cond(no)->op

Created with Raphaël 2.1.2 Start My Operation Yes or No? End yes no

example2

st=>start: 开始
e=>end: 结束
op=>operation: 操作
cond=>condition: 是或者不是？
subr=>subroutine: 子程序
out=>inputoutput: 输出

st->op->cond
cond(yes)->out->e
cond(no)->subr->op

Created with Raphaël 2.1.2 开始 操作 是或者不是？ 输出 结束 子程序 yes no

example3

st=>start: Start
e=>end: End
op1=>operation: My Operation
op2=>operation: Stuff
sub1=>subroutine: My Subroutine
cond=>condition: Yes
or No?
c2=>condition: Good idea
io=>inputoutput: catch something...

st->op1(right)->cond
cond(yes, right)->c2
cond(no)->sub1(left)->op1
c2(yes)->io->e
c2(no)->op2->e

Created with Raphaël 2.1.2 Start My Operation Yes or No? Good idea catch something... End Stuff My Subroutine yes no yes no