code optimization

I was reading through my programming book when I came upon two programs-one is a revisement of the other. The programs get your name, then print it on the screen, then print it backwards using pointers. The first version uses a for loop to get input

Code:

for(i=o; i<MAXSTRING; i++)
{
  buff[i]=getch();
  printf("%c", buff[i]);
  if(buff[i]==ENTER)
    {
      buff[i]= '\0';  /*puts null termination at end of string*/
      break;
    }
}

the second version uses a pointer

Code:

int main()
{
 char c, buff[MAXSTRING], *cptr;
 int length;

 cptr=buff;
 printf("Enter your name: ");
 while( (c=getch()) != ENTER)
   {
     *cptr=c;
     printf("%c",*cptr);
     cptr++;
   }
 *cptr='\0';
.......
}

I noticed that when the pointer is used it allows you to input past MAXSTRING (I used 15). I was wondering if there was a way to check to ensure that input doesn't overflow only using *cptr so that another variable doesn't have to be used. I tried adding an if statement inside the while loop to check if the value of buff[0] plus MAXSTRING would equal the value of *cptr (plus 15 bytes because it is only a char), and then if it was equal it would exit the loop. I tried this and it doesn't work

Code:

while( (c=getch()) != ENTER)
   {
     if(cptr==(&buff[0]+MAXSTRING)
       { break; }
     else  
      {
       *cptr=c;
       printf("%c",*cptr);
       cptr++;
       }
     }

Can this be done, and if so how?

Thanks for the help.
Re: Salem
>> I tried this and it doesn't work
>Can you be more specific?

Did you notice my third section of code that showed what I'd tried?

Between my sentece or two explaining what I had tried to do and the actual code I used when I changed the program I don't see how I could have given much more information. Past what I posted to you I didn't know what was going on or what part of my editing didn't work.

Code:

void rev( void )
{
    int c;
    if( (c = getchar()) != '\n' )
        rev( );
    putchar( c );
}

Wheee...

Code:

char buf[BUFSIZ];
char *ptr;

if( fgets( buf, BUFSIZ, stdin ) )
{
    for( ptr = buf+strlen(buf)-1; ptr>= buf; ptr-- )
        putchar( *ptr );
}

Ooooooh. Aaaaah.

Quzah.