Using Malloc and assigning to Arrays between functions

Question

I'm getting this error on line #4 which says 'invalid initializer'. I know what the error means, but I can't work out why i'm getting the error. I've tried all sorts of combinations of pointers and values, but it doesn't seem to want to work. Any help / feedback for the code would be greatly appreciated.

Note: I plan to have a 2D array for the chessboard, which mean 64 ints of memory malloc'd. The printf is there to keep the compiler happy and show me whether at [4][2] there is a '0'.

int *newBoard();    
int main(int argc, char *argv[]) {

   int *chessBoard[7][7] = *newBoard();
   printf ("%d", chessBoard[4][2]);

   return EXIT_SUCCESS;
}

int *newBoard() {

   int counter = 0;
   int *blankBoard = malloc(sizeof((int) * TOTALSPACES));

   while (counter < TOTALSPACES) {
      blankBoard[counter] = VACANT;
      counter++;
   }

   return blankBoard;
}

John3136 · Accepted Answer · 2014-02-08 05:20:36Z

1

newBoard returns an array of TOTALSPACES ints. int *chessBoard[7][7] = *newBoard(); LHS is a 7x7 array of int pointers (not ints). RHS is what, the contents of of an int pointer returned by the call? (what do you think the * infront of the call to newBoard() is doing?

Either int *newBoard = newBoard(); (to use heap memory) or int newBoard[7][7]; (to use stack memory) would work. You are trying to do half of each!

answered Feb 8, 2014 at 5:20

John3136

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BlackMamba · Accepted Answer · 2014-02-08 07:38:18Z

0

int *chessBoard[7][7] stands for an 2D array(7*7), each element type is int*; but *newBoard() stand for an int element.

answered Feb 8, 2014 at 7:38

BlackMamba

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BLUEPIXY · Accepted Answer · 2014-02-08 09:46:17Z

0

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

#define TOTALSPACES 8*8
#define VACANT '0'

void *newBoard();

int main(int argc, char *argv[]) {

    int (*chessBoard)[8][8] = newBoard();
    printf ("%d", (*chessBoard)[4][2]);//48 : '0'

    return EXIT_SUCCESS;
}

void *newBoard() {
    int *blankBoard = malloc(sizeof(int) * TOTALSPACES);
    int counter = 0;

    while (counter < TOTALSPACES)
        blankBoard[counter++] = VACANT;

    return blankBoard;
}

answered Feb 8, 2014 at 9:46

BLUEPIXY

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