Thread: Still having a little trouble w/th ptrs

I have implemented that delwhitespace code. Pretty neat little code. Thanks heaps for that. I am able to compile it, but it does not do anything. As it will not enter my while loop, which originally worked.
Here the while statement:

Code:

while( fgets( ptrstr, 80, file ) != NULL )
{
    delspace( ptrstr );
    fwrite( (void *) ptrstr, sizeof( char * ), strlen( ptrstr ), compfile );
    printf("%d%p\n", strcompare( ptrstr, ptroldstr ), ptrstr );
    strcpy( ptroldstr, ptrstr );
}

Thanks for that. I ll try it out straight away. The ptrstr is declared as follows:

Code:

    char *ptrstr, *ptroldstr;     

    /*create memory for the two string pointers */
    ptrstr = ( char * ) malloc( sizeof( char ) * 80 ); 
    ptroldstr = ( char * ) malloc( sizeof( char ) * strlen( ptrstr ));

For more details see attachment. Appreciate the help. Its been bugging me all week.Cheers, Johannes

Ta for that. I can see what you mean. What just blows me out of sanity is why the stupid while loop is not once used when compiling it. If I put as puts() before the while loop it will compile and display it, once I put a puts() within the while loop, NOTHING. The while loop was working before but?? Thats programming for you. U solve one problem and fall over the next one.
Have you got an idea what might cause that problem?Cheers, Johannes

Thank you so much for that. i have been looking at the code all afternoon and couldnt quite see what went wrong. And the int solution ( &int ) is just what I was trying to think of. Now if I get you right, fwrite is writing in binary? How do I write to file so that you can view it in a text file then? Coz I think thats what we are to do for the assignment.

Thanks so much for the help.
Cheers,
Johannes

thanks for the help. I got it to sorta work. I am still getting a "segmentation fault - core dumped" message tho.

Code:

while( fgets( ptrstr, 80, file ) != NULL )
    {   
        delspace( ptrstr );
        result = strcompare( ptrstr, ptroldstr );       
        printf( "%d%s", result, ptrstr );
        fwrite( &result, sizeof( int ), 1, compfile );
        fwrite( ptrstr, sizeof( char ), strlen( ptrstr ), compfile );
        strcpy( ptroldstr, ptrstr );
puts( "I WANT MORE" );
    }

puts( "I WANT EVEN MORE" );/*segmentation fault comes here*/

    fclose( file );
    fclose( compfile );
    return 0;
}

The other thing is with strcpy in my compare function. It says:

deltest.c: In function `strcompare':
deltest.c:135: warning: passing arg 2 of `strcpy' makes pointer from integer without a cast

Code:

int strcompare( char *ptrstr, char *ptroldstr )
{
    int i;
     
    if( strlen( ptroldstr ) == 0 )
    {
        ptroldstr = ptrstr;
        return 0;
    }
    for( i = 0; i < strlen( ptrstr ); ++i)
       if( *( ptrstr + i ) != *( ptroldstr + i ) )
           break;
        
    ptroldstr = strcpy( ptrstr, ptrstr[ i ] );
    return i;
        
}

I had that warning quite freqquently in earlier stages but I am not quite sure what thats supposed to mean for me?
Any hints, ideas appreciated. Cheers,
Johannes

Thanks for merging the threads. I had a look at the faq's but I had trouble finding information on how to subscribe, unsubscribe from threads, how to close a thread or if we have the ability to do so.
Cheers,
Johannes

One of my lecturers who s also teaching C, said that I am loosing oldptrstr at some point and that I have to updated it. I am just not sure exactly where and how. I played around with it this afternoon and I couldnt get it to work properly. Also he mentioned that hardcoding malloc with the 80 is inefficient.
Would it be more efficient if I was to malloc within the while loop of main and instead of 80, strlen( ptrstr )?
Anyway, here the sample file given to us containing the names. Thanks heaps,
Johannes

I just compiled and ran my part 2 of the assignment, where the uncompression is supposed to take place. It is compiling and runing but if you view the created text file, it has done absolutely nothing to the contents of the file! I dont see why. All these lines of code in the functions, and nothing happens. Any idea what I oversaw when I coded it last night and this afternoon?

[quote]'The more I try, the more I understand. The annoyance of not seeing the wrong seems huge, but its worth every effort'[quote]

Yeah that with the char [] is what my lecturer says too. But would it work with malloc in the while, or is it a better idea to go off an change all my ptrstr s to char[]?
Also I dont quite see what you mean? I am having trouble to visualise that part of the function. Even when I take a piece of paper and a pen I dont quite seem to get the picture.
Cheers,
Johannes
PS: I ended up using the '&' because it gave me all these warnings before. It was kind of an intelligent guess?

'The more I try, the more I understand. The annoyance of not seeing the wrong seems huge, but its worth every effort'