Difference between pre-increment and post-increment

[Kasya]

Difference between x++ and ++x;
Difference between x-- and --x;

[Banfa]

++x is pre-increment and x++ is post-increment that is in the first x is incremented before being used and in the second x is incremented after being used.

This is most easily demonstrated with a small program

#include <stdlib.h>
#include <stdio.h>

int main(int argc, char **argp)
{
    int x = 5;

    printf("x=%d\n", ++x);
    printf("x=%d\n", x++);
    printf("x=%d\n", x);

    return EXIT_SUCCESS;
}

The output of this program is

x=6
x=6
x=7

In the first printf statement x is incremented before being passed to printf so the value 6 is output, in the second x is passed to printf (so 6 is output) and then incremented and the 3rd printf statement just shows that post increment following the previous statement by outputting x again which now has the value 7.

[Kasya]

Difference between x-- and --x;

[Banfa]

I would have thought you could have modified the program I posted to find out, where ++ is increment -- is decrement, apart from that that act in a similar manor.

[Kasya]

Thanks!!!!!

[maan]

Thanks!!!!!

an other method
m+=1; is post increment
or m-=1 is post decrement

[JosAH]

an other method
m+=1; is post increment
or m-=1 is post decrement

Have you tried it? The value of the expression "m+=1" equals "m+1" so it is
more like a pre increment.

kind regards,

Jos

[maan]

yes i tried practicaly " m+1" is eqal to "m+=1"

"++m" is pre increment

if you have any other idea please reply

i'll wait 4 ur +ive response

Regardz Maan....

[JosAH]

yes i tried practicaly " m+1" is eqal to "m+=1"

"++m" is pre increment

Erm, yes that's what I wrote; you wrote that m+= 1 had the same value as
the *post* increment expression (see above).

kind regards,

Jos

[mistiq]

thank u buddy...i had the same question and ur answer really worked out:)

[chandu google]

i++ the post increment means after the after executing the value is increased. ++i is the preincrement it is before the executing the value is increased.

[cybosofttech]

++ operator is called increment operator . ++[variable] is called preincrement operator and [variable]++ is called post increment operator.

The preincrement operator first increment operator will increment the value stored in variable and then returns the stored value.

[Regila Mary]

what is the output of the following programs....

main()
{
  int c,i=5;
  if(i<10)
  {
     i++;
     c=i;
     cout<<c;
   }
}

what is the output????
Than,,,

main()
{
  int c,i=5;
  if(i<10)
  {
     ++i;
     c=i;
     cout<<c;
   }
}

what is the output????
I think the above 2 program got the same output. them y u use a pre and post incerment opretor?????

[donbock]

The difference between pre-increment and post-increment is whether the increment takes place before or after the value is used. Line 6 (in both snippets) does not use the value, so there is no discernible difference between the two kinds of increment.

To see a difference, combine lines 6 and 7 into a single line; for example:

c = i++;

or

c = ++i;

[AceInfinity]

@maan - No, you're wrong... m+1 is not the same as m+=1. m+1 holds the value of m after m+=1, but for m+1, the value of m will still be (m+1)-1, because that added 1 is not stored in the variable m.

edit: m=m+1 is the same as m+=1.