![FIX [error] system was not declared in this scope Programming in C tutorial for beginners lesson 3 - YouTube FIX [error] system was not declared in this scope Programming in C tutorial for beginners lesson 3 - YouTube](https://i.ytimg.com/vi/WisHmWWVdiU/maxresdefault.jpg)
FIX [error] system was not declared in this scope Programming in C tutorial for beginners lesson 3 - YouTube
![error compiling: 'D1' was not declared in this scope · Issue #18 · nidayand/motor-on-roller-blind-ws · GitHub error compiling: 'D1' was not declared in this scope · Issue #18 · nidayand/motor-on-roller-blind-ws · GitHub](https://user-images.githubusercontent.com/28128937/45780369-4d78dd80-bc12-11e8-837b-a61641f9c1ec.png)
error compiling: 'D1' was not declared in this scope · Issue #18 · nidayand/motor-on-roller-blind-ws · GitHub
![exit status 1'SensorPin' was not declared in this scope//How to fix the error while compiling//part4 - YouTube exit status 1'SensorPin' was not declared in this scope//How to fix the error while compiling//part4 - YouTube](https://i.ytimg.com/vi/NgaBNfxTBU8/maxresdefault.jpg)
exit status 1'SensorPin' was not declared in this scope//How to fix the error while compiling//part4 - YouTube
![exit status 1'SensorPin' was not declared in this scope//How to fix the error while compiling//part4 - YouTube exit status 1'SensorPin' was not declared in this scope//How to fix the error while compiling//part4 - YouTube](https://i.ytimg.com/vi/rr2fM-kg4vo/maxresdefault.jpg)
exit status 1'SensorPin' was not declared in this scope//How to fix the error while compiling//part4 - YouTube
![ubuntu 18.04 -->> error: 'floor' was not declared in this scope / error: 'sqrt' was not declared in this scope · Issue #3 · CogChameleon/ChromaTag · GitHub ubuntu 18.04 -->> error: 'floor' was not declared in this scope / error: 'sqrt' was not declared in this scope · Issue #3 · CogChameleon/ChromaTag · GitHub](https://user-images.githubusercontent.com/22295169/57237570-cbfe8000-7027-11e9-8cb5-51085d353d35.png)