Path: utzoo!attcan!uunet!lll-winken!lll-tis!ames!husc6!rutgers!gatech!gt-eedsp!baud
From: baud@gt-eedsp.UUCP (Kurt Baudendistel)
Newsgroups: comp.lang.c++
Subject: operator precedence question
Keywords: c++, precedence
Message-ID: <347@gt-eedsp.UUCP>
Date: 19 Jul 88 15:32:10 GMT
Distribution: na
Organization: School of Electrical Engineering, Ga. Tech, Atlanta, GA  30332
Lines: 33

in the following code fragment,

foo(char *s, char *t) {
  char *r = "hello, there";
  ...
  for ( int i=0, t=s; i < 10; i++ ) *t++ = *r++;
  ...

your initial reaction is that everything is okay, and that this will
copy the first 10 characters of "hello, there" into the buffer
pointed to by s.

however, this is not the case (at least with my compiler -- gnu g++).
what the compiler thinks is that the portion of the for statement

  "int i=0, t=s;"

is a statement which says "declare 2 integers i and t, and initialize
them to the values '0' and 's', respectively."  this also creates an
error to the effect that s is the wrong type (a pointer to char rather
than an int, but that is not relevant here).

it seems strange to me that when i used then `poor' variable declaration
technique of c (define all variables like `i' at the beginning of the
module) that the comma operator was a valuable part of the for statement
syntax, but that conversion to `proper' c++ variable declaration
technique (at the point of usage) invalidates the format of the for
statement.  why is this?

-- 
Kurt Baudendistel [GRA McClellan]
Georgia Tech, School of Electrical Engineering, Atlanta, GA  30332
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