dev-cpp-users

[Dev-C++] compilation error with ++ operator on char array

[Dawood V. <da...@ku...>]

I do not know, what's wrong with the code below:  It simply gives me=
=20
compilation error.  The compilation log is as follows:
D:/Documents/C_Notes/try.cpp: In function `int main()':
D:/Documents/C_Notes/try.cpp:11: non-lvalue in increment
The offending line is "if (*inp++ =3D=3D '?') count++;"  But the funn=
y thing is=20
if I substitute p for inp in the while loop, then it compiles and giv=
es me=20
the right answer.

I am under the impression that the post and pre increment operators c=
an be=20
used on the names of char arrays.  Somebody, please clear me on this =
and=20
give me some plausible explanation.

#include <cstdlib>
#include <iostream>
using namespace std;

int main()
{
     char inp[] =3D "?cmewop? OWCOIJJJ?mcjmwow? cwjw?xjw?";
     char* p =3D inp;
     int count =3D 0;
     while (*inp)
      if (*inp++ =3D=3D '?') count++;


     cout<<count<<'\n';

    system("PAUSE");
    return 0;

}

Re: [Dev-C++] compilation error with ++ operator on char array

[w.y. <yok...@ve...>]

Dawood Vora wrote:
> 
> The offending line is “if (*inp++ == '?') count++;”  But the funny
> thing is if I substitute p for inp in the while loop, then it compiles
> and gives me the right answer.

That is normal behavior.

> I am under the impression that the post and pre increment operators
> can be used on the names of char arrays.  Somebody, please clear me on
> this and give me some plausible explanation.
> 
>     char inp[] = "?cmewop? OWCOIJJJ?mcjmwow? cwjw?xjw?";

When you declare an array like this, 'inp' is essentially _constant_
and always contains the address of the first array element during its
lifetime.

>     char* p = inp;

p however you can change around as you already know.