Code:#include <stdio.h> #include <stdlib.h> #include <time.h> int printboard( int **board,int N); int main() { int i,j; int N=5; int board[N][N]; for(i=0;i<N;i++){ for(j=0;j<N;j++){ board[i][j]=1; } } printboard( board,N); return 0; } int printboard( int **board,int N){ int i,j; for(i=0;i<N;i++){ for(j=0;j<N;j++){ printf("%d",board[i][j]); } } }
Code:#include <stdio.h> #include <stdlib.h> #include <time.h> #define SIZE 5 void printboard(int board[][SIZE]); int main() { int board[SIZE][SIZE]; for (int i = 0; i < SIZE; i++) for (int j = 0; j < SIZE; j++) board[i][j] = 1; printboard(board); return 0; } void printboard(int board[][SIZE]) { for (int i = 0; i < SIZE; i++) { for (int j = 0; j < SIZE; j++) printf("%2d ", board[i][j]); putchar('\n'); } }
A little inaccuracy saves tons of explanation. - H.H. Munro
thing is i need to get the size from the console with argv.i just simplified the problem so you can send me an easy fix
The issue you have is that when an array is passed as an argument, it is converted to a pointer to its first element. This means that an array of arrays is converted to a pointer to an array, not a pointer to a pointer. This is why john.c's example retains the SIZE in the parameter.
Note that your array of arrays is actually a variable length array, whereas you probably want a fixed size array as shown by john.c.
Look up a C++ Reference and learn How To Ask Questions The Smart WayOriginally Posted by Bjarne Stroustrup (2000-10-14)
If you really want to use a variable-size array, then maybe something like this.
I also randomized the values.
Code:#include <stdio.h> #include <stdlib.h> #include <time.h> void printboard(int Size, int board[][Size]) { for (int i = 0; i < Size; i++) { for (int j = 0; j < Size; j++) printf("%2d ", board[i][j]); putchar('\n'); } } int main(int argc, char **argv) { int Size = 5; if (argc > 2) { fprintf(stderr, "Usage: board [SIZE]\n"); return EXIT_FAILURE; } if (argc == 2) Size = atoi(argv[1]); if (Size <= 0) { fprintf(stderr, "The size must be > 0\n"); return EXIT_FAILURE; } int board[Size][Size]; for (int i = 0; i < Size; i++) for (int j = 0; j < Size; j++) board[i][j] = rand() % 2; printboard(Size, board); return 0; }
Last edited by john.c; 01-28-2020 at 03:12 PM.
A little inaccuracy saves tons of explanation. - H.H. Munro
Interesting. I didn't know this!
I prefer to deal with multidimensional arrays as an argument through a single pointer:
Code:void f(int size, int *ptr) { int i, j, *p; for ( i = 0; i < size; i++ ) for ( j = 0; j < size; j++ ) { p = ptr + size * j + i; // p points to "ptr[i][j]". ... } }
> why do i get segmentation fault here?and how do i fix it?
You read the error message and fix the code, before trying to run it.
That warning that was printed in your screen shot wasn't a slap on the wrist, it was a gun at your head.
If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
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