Xref: utzoo comp.lang.c:38082 comp.std.c:4640
Newsgroups: comp.lang.c,comp.std.c
Path: utzoo!utgpu!cunews!bnrgate!bwdls61!bwdla28!coop4y44
From: coop4y44@bwdla28.bnr.ca (Takis Skagos)
Subject: Re: difference between c++; and ++c;
Message-ID: <1991Apr9.125207.22511@bwdls61.bnr.ca>
Summary: Diff's between ++c and c++
Keywords: pre post increment decrement grammar style
Sender: usenet@bwdls61.bnr.ca (Use Net)
Organization: Bell-Northern Research, Ottawa, Canada
References: <1991Apr08.161444.10025@cs.ruu.nl> <1817@bbxsda.UUCP>
Date: Tue, 9 Apr 1991 12:52:07 GMT

In article <1991Apr08.161444.10025@cs.ruu.nl> hnridder@cs.ruu.nl (Ernst de Ridder) writes:
>	while ( c < 100)
>	   ++c;
>instead of
>	while ( c < 100)
>	   c++;
>
>Why should one of these forms be preferred over the other in such a situation,
>apart from personal preferences?

  Well, ++c is incrimented before c is used and c++ is used before it
is incrimented.  As you're using it, it doesn't matter, but here is a
sample program that you can try:

main()
{
  int a,b,c;
  a=b=0;
  for (c=0;c<=40;c++)
    printf(" a := %4d\tb:= %4d\n",a++,++b);
}

  When you execute the program you will get:
 a :=    0      b:=    1
 a :=    1      b:=    2
 a :=    2      b:=    3
           ... 
 a :=   38      b:=   39
 a :=   39      b:=   40
 a :=   40      b:=   41

  So you see, 'a' is used before it is incrimented and 'b' is incrimented
before it is used.  In the 'for' statement, it doesn't matter whether
we use '++c' or 'c++'.

                                             Taki

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BNR Ottawa           Disclaimer:  "I swear, they made me do it!"
P. Takis Skagos 
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