Pointer as permater

[evanc9606]

Okay so I am trying to have a function fill a 2d char array with values, but I keep getting an error of incompatible pointer type.

#include <stdio.h>

void plusone(int *p) {
  ++*p;
}

void generateboard(char *array[10][10]) {
  for (int y = 0; y < 10; ++y) {
    for (int x = 0; 2 < 10; ++x) {
      *array[y][x] = '*';
    }
  }
}

void printboard(char array[10][10]) {
  for (int y = 0; y < 10; ++y) {
    for (int x = 0; 2 < 10; ++x) {
      printf("%c", array[y][x]);
    }
  }
}

int main(void) {
  int i = 10;
  char board[10][10];
  printf("i is %d\n", i);

  plusone(&i);
  printf("i is now %d\n", i);

  generateboard(&board[0][0]);
  printboard(board);

  return 0;
}

The error is only happening with the 2d char array.
Can someone help me pass the pointer to the function properly?

[hamsterman]

board is an array of chars, so board[0][0] is a char and &board[0][0] is a char*, rather than char* array[10][10] (which is a 10*10 array of char pointers, by the way).
You can make it work the same way as printboard. Arrays are passed by reference. If you think that you need a pointer to an array, though, the argument is char (*array)[10][10] and you need to pass &board and access elements with (*array)[x][y], I think..

[evanc9606]

I will try that, I am poiting to the array because I want the changes of the array to make it back to the main function. The generateboard function will only change a copy of the original array if I just pass it in like with the printfboard function.

[evanc9606]

Now it compiles without errors but the application itself crashes, here is the new code.

#include <stdio.h>

void plusone(int *p) {
  ++*p;
}

void generateboard(char (*array)[10][10]) {
  for (int y = 0; y < 10; ++y) {
    for (int x = 0; 2 < 10; ++x) {
      *array[y][x] = '*';
    }
  }
}

void printboard(char array[10][10]) {
  for (int y = 0; y < 10; ++y) {
    for (int x = 0; 2 < 10; ++x) {
      printf("%c", array[y][x]);
    }
  }
}

int main(void) {
  int i = 10;
  char board[10][10];
  printf("i is %d\n", i);

  plusone(&i);
  printf("i is now %d\n", i);

  generateboard(&board);
  printboard(board);

  return 0;
}

[evanc9606]

Noticed that I didn't use (*array)[y][x]. Changeing it didn't stop the crashing though

[z05DSL3A]

for (int x = 0; 2 < 10; ++x) would be a big problem.

You will also want to deference array before offsetting it; (*array)[y][x] = '*';

NB: array is not a very good name for the array.

[evanc9606]

OMG how did I ever miss that!

[evanc9606]

Now the program is still crashing and the output is horrable. I get really wierd symbols filling the console and my computer starts beeping. Never had that before

[z05DSL3A]

Did you notice my edit about dereferencing array?

[evanc9606]

Using a different compiler I am warned about an infinite loop and unreachable code. But I can't figure out where that is.

[evanc9606]

Here is my up-to-date code. Yes I know that array is not a very good variable name, but this is just a test program because I am trying to get this to work for a different application.

#include <stdio.h>

void generateboard(char (*array)[10][10]) {
  for (int y = 0; y < 10; ++y) {
    for (int x = 0; x < 10; ++x) {
      (*array)[y][x] = '*';
    }
  }
}

void printboard(char array[10][10]) {
  for (int y = 0; y < 10; ++y) {
    for (int x = 0; 2 < 10; ++x) {
      printf("%c", array[y][x]);
    }
  }
}

int main(void) {
  char board[10][10];

  generateboard(&board);
  printboard(board);

  return 0;
}

EDIT:Wow i could have sworn I fixed the for loop and yet above it is still their

[z05DSL3A]

Here is an edit of your code that should work:

#include <stdio.h>

void plusone(int *p) {
  ++*p;
}


void generateboard(char (*board)[10][10]) {
  for (int y = 0; y < 10; ++y) {
    for (int x = 0; x < 10; ++x) {  // Fixed
      (*board)[y][x] = '*';         // Fixed
    }
  }
}

void printboard(char board[10][10]) {
  for (int y = 0; y < 10; ++y) {
    for (int x = 0; x < 10; ++x) {  //Fixed
      printf("%c", board[y][x]);
    }
  }
}

int main(void) {
  int i = 10;
  char board[10][10];
  printf("i is %d\n", i);

  plusone(&i);
  printf("i is now %d\n", i);

  generateboard(&board);
  printboard(board);

  return 0;
}

[evanc9606]

Thankyou it works now. I am guessing that i had copied the first for loop with the the problem you pointed out and didn't notice I had that problem in two places.