Use this tag for questions regarding programming (writing code) for Arduino. This can include problems with code you've written for Arduino, or questions about how/why Arduino code acts in certain ways.
Where a question relates to a particular language, you can also use language-specific tags, such as c++.
Programming questions which are not specific to Arduino (e.g. general questions about a programming language) should be asked on Stack Overflow instead.
For questions regarding uploading sketches to Arduino devices, please use the uploading tag.