哪个公司？报一下别让后来的同学掉坑里。

@cjpjxjx 台湾工资二十年不涨了。。

这个版本很垃圾不要用，如果非要用 Ubuntu 换 16.04

@Linxing 老哥怎么实现

顺手给你加个引用"The distinction between a declaration and a definition may seem obscure at this
point but is actually important.To use a variable in more than one file requires
declarations that are separate from the variable ’ s definition. To use the same variable
in multiple files, we must define that variable in one and only one file. Other files
that use that variable must declare but not define that variable."

example:
"extern double pi = 3.1416; // definition"

详见<C++ Primer 5th> "2.2.2. Variable Declarations and Definitions"