I wonder why initailizing an array got an unexpected result

[melodynk]

Hi ,all
I would like to initailize an array in root terminal using this way : int d[40]=100
but I could not get the correct return result [100, 100, 100, 100, 100…]
instead get the figure below. I wonder it is normal?
Many Thanks!

[Wile_E_Coyote]

cppreference.com → Array initialization
Uncle Google → C++ initialize all elements of an array

[melodynk]

Thanks so much. I know the principle . Another question confusing me . I wonder why a[1] a[2] a[3] printing value 2 below? Thanks so much!

[Wile_E_Coyote]

Which operating system, which ROOT version.

[couet]

I do not see this effect with recent ROOT versions (on MacOS):

% root
   ------------------------------------------------------------------
  | Welcome to ROOT 6.27/01                        https://root.cern |
  | (c) 1995-2022, The ROOT Team; conception: R. Brun, F. Rademakers |
  | Built for macosx64 on Nov 24 2022, 06:43:42                      |
  | From heads/master@v6-25-02-2828-g33beda7d0d                      |
  | With Apple clang version 14.0.0 (clang-1400.0.29.202)            |
  | Try '.help'/'.?', '.demo', '.license', '.credits', '.quit'/'.q'  |
   ------------------------------------------------------------------

root [0] int a[40] = {2}
(int [40]) { 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 }
root [1] a[0]
(int) 2
root [2] a[1]
(int) 0
root [3] 

[melodynk]

The version is 6.24.00. OS is windows 10.The compiler provided by visual studio

[Wile_E_Coyote]

That’s very old.
Take the “Latest Release”.

[bellenot]

That’s a known issue. See [cling,win32] Read-after-write of variable of type `double` does not yield the correct result · Issue #9809 · root-project/root · GitHub

[melodynk]

OK,thanks!

[melodynk]

Thanks!