Thread: Passing incompatible pointer type?

This is example code straight out of the book, and I have no idea what the problem with it is.


fig07_24.c: In function ‘main’:
fig07_24.c:21: warning: passing argument 1 of ‘deal’ from incompatible pointer type
fig07_24.c: At top level:
fig07_24.c:44: error: conflicting types for ‘deal’
fig07_24.c:6: error: previous declaration of ‘deal’ was here


Does anyone have a clue please?

Code:

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

void shuffle( int[][ 13 ] );
void deal( const int[][ 13 ], const char *[], const char *[] );

int main()
{
   const char *suit[ 4 ] = 
      { "Hearts", "Diamonds", "Clubs", "Spades" };
   const char *face[ 13 ] = 
      { "Ace", "Deuce", "Three", "Four", 
        "Five", "Six", "Seven", "Eight", 
        "Nine", "Ten", "Jack", "Queen", "King" };
   int deck[ 4 ][ 13 ] = { 0 };

   srand ( time( 0 ) );

   shuffle( deck );
   deal( deck, face, suit );

   return 0;
}


void shuffle( int wDeck[][ 13 ] )
{
   int row, column, card;

   for (card = 1; card <= 52; card++) {
      do {
         row = rand() % 4;
         column = rand() % 13;
      } while( wDeck[ row ][ column ] != 0 );

      wDeck[ row ][ column ] = card;
   }
}


void deal( const int wDeck[][ 13 ], const char *wFace[], const char 
           wSuit[] )
{
   int card, row, column;

   for (card = 1; card <= 52; card++)

      for (row = 0; row <= 3; row++)

         for (column = 0; column <= 12; column++)

	    if ( wDeck[ row ][ column ] == card )
	       printf(" %5s of %-8s%c",
               wFace[ column ], wSuit[ row ],
               card % 2 == 0 ? '\n' : '\t' );
}

Code:

void deal( const int[][ 13 ], const char *[], const char *[] );
void deal( const int wDeck[][ 13 ], const char *wFace[], const char 
           wSuit[] )

it seems your parameters dont match up:

Code:

void deal( const int[][ 13 ], const char *[], const char *[] );
// ...
void deal( const int wDeck[][ 13 ], const char *wFace[], const char wSuit[] )
{
//...

when you implement the function deal, the 3rd parameter should be *[] not just [].


for the error about parameter 1 of deal, it might be because deck is int[][] but your function accepts const int[][]. i thought you could just put 'const <datatype>' to treat it as const, but maybe something else is going on when your trying to do that on a 2-d array.

Adding the * did solve part of the problem, but I'm still getting

"
fig07_24.c: In function ‘main’:
fig07_24.c:21: warning: passing argument 1 of ‘deal’ from incompatible pointer type
"

I took out the const in front of int wDeck[][ 13 ] and the associated prototype, and I was able to compile the program without a problem. But I thought a function could use a non constant variable as a constant. Am I using the wrong version of C or something?

Originally Posted by yougene

I took out the const in front of int wDeck[][ 13 ] and the associated prototype, and I was able to compile the program without a problem. But I thought a function could use a non constant variable as a constant. Am I using the wrong version of C or something?

You should be able to, but then again, I don't see the point in doing so since you're passing by value and not by pointer.

change your function prototype ( i mean remove the const)

Code:

void deal( int[][ 13 ], const char *[], const char *[] );

and in the function definition (remove const)

Code:

void deal( int wDeck[][ 13 ], const char *wFace[], const char *wSuit[] )

ssharish

>>Elysia
I'm on the section where I'm learning about the principle of least privilege and pointers.

>>ssharish2005
That fix works ssharish, but was what I did wrong, or is this just a cryptic oddity?

It was late last night and I didn't notice the program compiles with the warning just fine. My mistake!

Thank you, although it's code from the book. I do try to stick to the books coding style as much as possible.