Quick Array Problem

**JaydinBane** · 04-03-2009

I have the following code:

Code:


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

int max_rows;
int max_columns;
void print(char[][]);

int main(int argc, char *argv[]){
	
	max_rows = 3;
	max_columns = 3;
	char grid[max_rows][max_columns];
	
	for(int i = 0; i < max_rows; i++){
		for(int j = 0; j < max_columns; j++){
			grid[i][j] = 'X';
		}
	}
	
	print(grid);
	
}

void print(char grid[max_rows][max_columns]){
	
	
	for(int i = 0; i < max_rows; i++){
		for(int j = 0; j < max_columns; j++){
			printf("%c ", grid[i][j]);
		}
		printf("\n");
	}
	
}

I get the following errors:

error: array type has incomplete element type (line: void print(char[][])

In function ‘main’:
error: type of formal parameter 1 is incomplete (line: print(grid)

Any ideas???

**quzah** · 04-03-2009

Compile in C99 mode, otherwise you can't do what you're trying to do. Also, multi-dimension arrays are converted to a pointer to their type. So an array of array of ints becomes a pointer to an array of ints. And, it doesn't like that you're trying to not tell it how big the array is in the function declaration.

Quzah.

**JaydinBane** · 04-03-2009

Could you possibly post an example of how to fix this?? I have to turn this in by midnight tonight and need to get it done. The reason I've set it up like this is because max_rows and max_columns will be specified by command line arguments.

**quzah** · 04-03-2009

Search the forums. Questions about creating dynamic arrays or dynamic multi-dimension arrays are pretty common.

Quzah.

**Adak** · 04-03-2009

This version runs well on old compilers:

Code:

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

int max_rows;
int max_columns;
//we can pass this way without knowing the values of max rows and columns
//we could change it, if we knew the sizes at this point
void print(char**);

int main(int argc, char *argv[]){
	
	char **grid;
   int i, j;
	max_rows = 3;
	max_columns = 3;


   *grid = malloc(max_rows * sizeof(char*));

   for(i = 0; i < max_rows; i++)
      grid = malloc(max_columns * sizeof(char));  //not a pointer size
   	
	for(i = 0; i < max_rows; i++){
		for(j = 0; j < max_columns; j++){
			grid[i][j] = 'X';
		}
	}
	
	print(grid);
   //free each row
	for(i = 0; i < max_rows; i++)
      free(grid[i]);
   //then free the whole array
   free(grid);

   printf("\n\n\t\t\t      press enter when ready ");
   i = getchar();
   return 0;
}

void print(char **grid) {
   int i, j;	
	
	for(i = 0; i < max_rows; i++){
		for(j = 0; j < max_columns; j++){
			printf("%c ", grid[i][j]);
		}
		printf("\n");
	}
	
}

**karthigayan** · 04-03-2009

Better you can check this program.It will work fine.

Code:

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

int max_rows;
int max_columns;
void print(char grid[]){
int i,j;

        for( i = 0; i < max_rows; i++){
                for( j = 0; j < max_columns; j++){
                        printf("%c ", grid[i]);
                }
                printf("\n");
        }

}


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

        max_rows = 3;
        max_columns = 3;
        int i,j;
        char grid[max_rows][max_columns];

        for( i = 0; i < max_rows; i++){
                for( j = 0; j < max_columns; j++){
                        grid[i][j] = 'X';
                }
        }

        print(grid[0]);

}

good luck..

**vart** · 04-03-2009

Originally Posted by karthigayan

Better you can check this program.It will work fine.
good luck..

As was already stated it will not work in the C90 mode

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