SIGSEGV (Segmentation Fault) upon setting character in char array (object member var)

[John Kiro via Digitalmars-d-learn]

Hello there,

First time to experiment with DLang, after a long time.
I'm getting a weird behavior with an **array of chars**, where I 
get a segmentation fault upon writing to it (see code and output 
below). What makes this problem weird it two things:

1) Why there is no problem with the **int** array (unlike the 
**char** array)?
2) Why reading the array element (**charArray[index]**) works, 
unlike writing to it?

The problem is gone if I uncomment the constructor code.

Code:

     import std.stdio;

     void main()
     {
       (new Test).runit();
     }

     class Test {
       static enum MAX = 10;
       uint index = 0;
       auto intArray = new int[MAX];
       auto charArray = new char[MAX];

       this() {
         /*
         charArray = new char[MAX];
         */
       }

       void runit() {
         debug writefln("IntArray initially: %s", intArray);
         intArray[index] = 40; //OK
         debug writefln("IntArray becomes: %s", intArray);

         debug writefln("Adding char in place of (%c) at index 
(%d)..",
                        charArray[index], index);
         charArray[index] = 'a'; //ERROR: segmentation fault 
(code -11)!
         debug writefln("CharArray becomes %s (PROGRAM ABORTS 
BEFORE IT ACTUALLY!)",
                       charArray);
       }
     }


Output:

     $ dub run
         Starting Performing "debug" build using 
/home/john/dlang/dmd-2.106.0/linux/bin64/dmd for x86_64.
         Building hello-dlang ~master: building configuration 
[application]
          Linking hello-dlang
          Running hello-dlang
     IntArray initially: [0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
     IntArray becomes: [40, 0, 0, 0, 0, 0, 0, 0, 0, 0]
     Adding char in place of (�) at index (0)..
     Error Program exited with code -11