I've been struggling with this problem for a while now, searching every possible solution. I'm new to C so I'ts hard. I know I have some variable uninitialized, but I can't find them. I am trying to print a matrix. Here's the constructor:
BoardP createNewBoard(int width, int high)
{
BoardP board = (BoardP) malloc(sizeof(Board));
if (board == NULL)
{
reportError(MEM_OUT);
return NULL;
}
board->height = high;
board->width = width;
board->board = (char**) malloc(high * sizeof(char*));
int i;
for (i=0; i<high; i++)
{
board->board[i] = (char*) malloc(width * sizeof(char));
if (board->board[i] == NULL)
{
freeTempBoard(board,i);
return NULL;
}
}
return board;
}
The constructor returns BoardP, a pinter to Board, which is:
typedef struct Board
{
int width;
int height;
char **board;
} Board;
Now I fail trying to print the board->board. I loop over the matrix and for each cell I call this function:
static void printChar(ConstBoardP board, int X, int Y)
{
if (X>=board->height || Y>=board->width)
{
printf(" ");
}
else
{
printf("%c ",board->board[X][Y]); //!!THIS IS LINE 299 IN Board.c!!
}
}
And fianlly here's the error I get:
==4931== Conditional jump or move depends on uninitialised value(s)
==4931== at 0x4E973D9: _IO_file_overflow@@GLIBC_2.2.5 (fileops.c:880)
==4931== by 0x4E6F01B: vfprintf (vfprintf.c:1614)
==4931== by 0x4E75879: printf (printf.c:35)
==4931== by 0x400D91: printChar (Board.c:299)
开发者_C百科==4931== by 0x400CED: printBoard (Board.c:284)
==4931== by 0x400F1A: main (PlayBoard.c:19)
==4931==
==4931== Conditional jump or move depends on uninitialised value(s)
==4931== at 0x4E97401: _IO_file_overflow@@GLIBC_2.2.5 (fileops.c:887)
==4931== by 0x4E6F01B: vfprintf (vfprintf.c:1614)
==4931== by 0x4E75879: printf (printf.c:35)
==4931== by 0x400D91: printChar (Board.c:299)
==4931== by 0x400CED: printBoard (Board.c:284)
==4931== by 0x400F1A: main (PlayBoard.c:19)
==4931==
==4931== Conditional jump or move depends on uninitialised value(s)
==4931== at 0x4E6F025: vfprintf (vfprintf.c:1614)
==4931== by 0x4E75879: printf (printf.c:35)
==4931== by 0x400D91: printChar (Board.c:299)
==4931== by 0x400CED: printBoard (Board.c:284)
==4931== by 0x400F1A: main (PlayBoard.c:19)
Now there's another file that calls createNewBoard, and then create printBoard(newBoard,0,0). The only thing that could possibly be uninitialized is board->board, other then that I have no ideas. I don't know how to debug it. I know its a lot of text, but I can't find the problem. Any idea would be much appreciated
Try:
for (i=0; i<high; i++)
{
board->board[i] = (char*) malloc(width * sizeof(char));
/* ... */
memset(board[i], 0, width);
}
malloc
does not initialize the memory, so this:
printf("%c ",board->board[X][Y]);
might be uninitialized. Use calloc
instead or add memset
after
board->board[i] = (char*) malloc(width * sizeof(char));
At the line:
board->board[i] = (char*) malloc(width * sizeof(char));
...you allocate space for the board row, but you never actually initialise the values in this array. Use memset(board[i], 0, width)
or explicitly loop over the array to set the values.
(Also, as a matter of style, you don't need to cast malloc
's return value.)
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