previous implicit declaration of some_function was here

转载
https://www.iteye.com/blog/wangleide414-1707160

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error: previous implicit declaration of ‘some_function’ was here的解决办法
error: previous implicit declaration of ‘some_function’ was here
Solution: Didn’t your programming teacher tell you to always make function prototypes? He/she had good reason. It’s also best to have them at the top, global space of the file, not in weird places. Yes, I have seen a function declared within another function, just before it gets called. Try to avoid that!

原因：注意函数在声明的时候注意顺序。

在写源代码的时候

|***********|

|** A******|

|** B******|

|***********|

其中A函数要调用B函数，此时就会在A函数处出现 previous implicit declaration of B was here的现象。

如果将代码改为

|***********|

|** B******|

|** A******|

|***********|此时在A里调用B便不会出现错误了.