预编译(preprocessing)

在cpp文件变成可以执行的exe文件之前，第一步需要做的就是预编译
https://www.jianshu.com/p/f46b05e8a0e8
https://www.jianshu.com/p/ab9d597d9b98
http://c.biancheng.net/view/2384.html
https://blog.csdn.net/czc1997/article/details/81175399
https://www.cnblogs.com/clover-toeic/p/3737129.html
https://www.runoob.com/w3cnote/gcc-parameter-detail.html
https://www.cnblogs.com/ggjucheng/archive/2011/12/14/2287738.html
https://www.cnblogs.com/wfwenchao/articles/4140771.html