Hi,
does the assignment operator copy all the members also for structures containing STL objects (strings,vectors,vectors of vectors...)?

I did try it on my platform,and it works that way (copying all the fields),but i was wondering if it is a standard behavior or not.

Thanks in advance!

Yes it is standard behavior.

Assuming you do not define an assignment operator for your struct, the compiler will create an assignment operator for your struct and that assignment operator will use the assignment operators of each member of the struct.

The assignment operator for std::vector copies the contents (so a vector of vectors would be "deep copied" by assignment). Other STL object behave in similar manners.

But remember that assigning a pointer just copies the pointer. It does not copy the object. If your struct contains pointers, you should give some thought to how those pointers should be treated during assignment. Probably, you would want to write an assignment operator to implement the way you want the members that are pointers copied. Then you take over responsibility for assigning all the members, not just those that are pointers.

std::vector internally uses a pointer for its buffer space. So inside the source code of std::vector it was not possible to use the default assignment operator that the compiler would provide. Instead the source code of std::vector includes an assignment operator that correctly assigns that pointer. When you use std::vector you don't need to worry about those details. When you use pointers in structs (as std:vector does internally) you do need to worry about those details.

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Thank you :-)