Is there a construct like Java initializing blocks in C++?

Question

I read in some articles that there is something called Initializing blocks in java ; where we can perform some initializing assignments When the Class is loaded or an instance is created.

Apart from methods and constructors, Initialization Blocks are the third place in a Java Program where operations can be performed.

class InitDemo
{
     static int y;
     int x;
 {
   y = 10;
   x =  0;
 }
}

I am asking if there is such paradigme in C++ ? Thank you.

Answer 1

It needs to be pointed out that there are two different forms of initialization blocks in Java. The bare {...} block, without the keyword static, is just a bit of compiler swizzling -- the text in the block is appended to the front of any constructors that are defined -- no separate code segment is generated. A block that begins static {..., on the other hand, is a static initialization block and a (semi-)proper procedure in its own right (named, not surprisingly, "static").

The static block is executed only once, immediately (with a few caveats) after the class is loaded. The non-static initializer is (by virtue of being copied into the constructors) executed every time a constructor is executed, and hence is generally inappropriate for static init.

Answer 2

In a nutshell, C++ does not have a direct equivalent for this Java construct.

To get similar behaviour, you would have to set x and y from InitDemo's constructors (which you can also do in Java).