This comes historically from the C, where a `struct` is considered as a type declaration and it allows to do:
**Xeus-cling issue:** Here cling doesn't manage to compile it but it is accepted rightfully by a full-fledged compiler (see for instance [@Coliru](http://coliru.stacked-crooked.com/a/3b77606ea8082485)):
This comes historically from the C, where a `struct` could be defined and initialized at the same time (or should - Xeus-cling doesn't manage it... As usual you may check a full-fledged compiler accepts it [@Coliru](http://coliru.stacked-crooked.com/a/3b77606ea8082485)):
%% Cell type:code id: tags:
``` C++17
// Xeus-cling issue (at least circa May 2021)
struct Vector
{
double x;
double y;
double z;
...
...
@@ -146,11 +146,11 @@
v1.z = -2.;
```
%% Cell type:markdown id: tags:
This is the reason why a semicolon is always required at the end of a `struct` or a `class` declaration.
This is absolutely **not** encouraged in C++, but it may help you to remember always closing a `struct`(or later a `class`) with a semicolon.
