这是一个链接错误。 LD 是连接器，所以如果你用LD返回退出状态1结尾的错误信息，告诉你，这是一个链接错误。

It's a linker error. ld is the linker, so if you get an error message ending with "ld returned 1 exit status", that tells you that it's a linker error.

该错误消息告诉你，没有你链接到的目标文件包含 avergecolumns 的定义。其原因是，你所定义的函数被调用 averagecolumns （换句话说：调用的函数（和presumably当你拼错函数名头文件，以及 - 否则你不得不在编译时））得到一个不同的错误

The error message tells you that none of the object files you're linking against contains a definition for avergecolumns. The reason for that is that the function you've defined is called averagecolumns (in other words: you misspelled the function name when calling the function (and presumably in the header file as well - otherwise you'd have gotten a different error at compile time)).