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Not on their own. A full if, for or while (with the conditions and body) is usally a statement, and might be an expression in some languages.

The body is also not terminated by a semicolon.

`while (true) { puts("Hello World\n"); };`

What you've written there does compile though, which was the original condition :).

I get the joke, but it's two statements, not one. (while and ;)

In JavaScript no. But in some languages it can be.

No. Those are syntactic elements.