Path: utzoo!mnetor!uunet!lll-winken!lll-lcc!ames!necntc!linus!mbunix!jfjr
From: jfjr@mitre-bedford.ARPA (Jerome Freedman)
Newsgroups: comp.lang.c
Subject: Arrays and structures
Message-ID: <22151@linus.UUCP>
Date: 19 Jan 88 20:12:22 GMT
Sender: news@linus.UUCP
Reply-To: jfjr@mbunix (Freedman)
Organization: The MITRE Corporation, Bedford, Mass.
Lines: 57



Suppose I have the following

typedef struct /* I despise structure tags */
  { 
    /* some irrelevant field declarations */
   char string[80];
   int  vector [4];
  } structure_type;


structure_type first_structure,second_structure;

/* The various fields of first_structure get filled */
/* and  somewhere in the code I do this             */

second_structure = first_structure; /* ANSI standard allows this */

Now, tell me about the string and vector fields of second structure.
Since they are arrays then the fields are actually pointers. The
question is: are the string and vector fields of "second_structure"
pointing ad the same addresses as the corresponding fields of
first structure or are they pointing to different areas of
memory into which the contents of the arrays pointed to
in first_structure have been copied(whew - what I meant not
what I said)??

Is the situation different if I change the type declaration to



typedef struct /* I despise structure tags */
  { 
    /* some irrelevant field declarations */
   char *string;
   int  *vector;
  } structure_type;


structure_type first_structure,second_structure;

then I say first_structure.string = "some string";

second_structure = first_structure;




Jerry Freedman, Jr      "Thank you, folks,
jfjr@mitre-bedford.arpa   for those kind applause"
(617)271-4563            



Jerry Freedman, Jr      "Love is staying up all night 
jfjr@mitre-bedford.arpa   with a sick child,
(617)271-4563            or a healthy adult"