Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!columbia!cs!d-yang
From: d-yang@cs.columbia.edu (David Yang)
Newsgroups: comp.lang.c
Subject: Re: Help...
Summary: Need to allocate memory for the array
Message-ID: <372@cs.columbia.edu>
Date: 10 Oct 89 03:23:37 GMT
References: <731@carroll1.UUCP> <39902@bu-cs.BU.EDU>
Organization: Columbia University Department of Computer Science
Lines: 30

> dnewton@carroll1.UUCP (Dave 'Yes, I'm weird' Newton) said:
> 
> Dave> Why doesn't this work?
> 
> Dave> ==========================
> Dave> #include <stdio.h>
> Dave> main ()
> Dave> {
> Dave>    char      h[];
> Dave>    scanf ("%s", h);
> Dave>    printf ("%s\n", h);
> Dave> }
> Dave> ==========================
> 
char h[] doesn't reserve any memory for the array.
Try char h[some constant for the max str. length expected]
  e.g., char h[80];
You can see the difference if you "cc -S" both versions and use "diff",
  or whatever file comparing command your system has,
  on the .s (assembly language) files created.

Note that declarations like "char h[]" are okay for parameters of functions
  since in that case they are treated just like a pointer (i.e., char *h)
  since when an array is an argument in a function call, it's address gets
  passed.

Hope this was somewhat comprehensible,
David Yang
d-yang@cs.columbia.edu
the