![graph TD;
A-->B;
B-->C;](https://www.icode9.com/i/ll/?i=9823fb7b24344aec99c6022649fc5754.jpg?,type_d3F5LXplbmhlaQ,shadow_50,text_Q1NETiBAbTBfNjI3ODAxNzc=,size_20,color_FFFFFF,t_70,g_se,x_16)

学习了常量和变量，“\0”为字符串结束符，