Thread: returning a 2D array in a function

what i want is.....
in a function i have a paramater that takes a 2D array... than i want to manipulate that array and return it..!
the problems is it doesn't seems to return..

here is my codes....


#include <stdio.h>

/** Function protype **/
char fillArray(char map[][], char);

int main(){
char map[2][2];
map = fillArray(map, 'x');
printf("%s\n", map);
return 0;
}

/* fills the array with symbol */
char fillArray( char map[][], char symbol){
int i,j;
for(j=0; j<1; j++){
for(i=0; i<1; i++){
map[j][i]=symbol;
}
}
return map;
}

here is my errors...

PrintArray.c: In function `main':
PrintArray.c:10: incompatible types in assignment
PrintArray.c: In function `fillArray':
PrintArray.c:20: arithmetic on pointer to an incomplete type
PrintArray.c:23: warning: return makes integer from pointer without a cast


i'm really new to C... so you guys have any ideas?

Code:

#include <stdio.h>

/** Function protype **/
void fillArray(char map[][2], char);

int main () {
    char map[2][2];
    fillArray( map, 'x' );
    printf( "%2.2s\n", map[0] );    // these are not normal 'C' strings with a \0
    printf( "%2.2s\n", map[1] );    // at the end, so care is needed in printing
    return 0;
}

/* fills the array with symbol */ 
void fillArray( char map[][2], char  symbol) {
    int i,j;
    for(j=0; j<2; j++ ) {
        for(i=0; i<2; i++ ) {
            map[j][i]=symbol;
        }
    }
}

i've try the codes you give me... thx... it works fine...

i got a few questions..

in....
printf( "%2.2s\n", map[0] );
printf( "%2.2s\n", map[1] );

if i change to
printf( "%s\n", map[0] );
printf( "%s\n", map[1] );

why is that i get this result
xxxxØùÿ¿w!@
xxØùÿ¿w!@

i've got a java programming background
and i notice you can't return an array in C
is this true?

i've also replace
void fillArray(char map[][2], char)
with
void fillArray(char map[][], char)
why do i get an compile error??

also another question....

i notice you've defined a array size in the function prototype
void fillArray(char map[][2], char);
what is the size of the map is dynamic...

lets say a user input the size of the map... how would i achieve that... if we already set the size of the array?

> why is that i get this result
> xxxxØùÿ¿w!@
Didn't you read my previous post?

> and i notice you can't return an array in C
> is this true?
You can't return an array (by value), but you can always return an array by reference

> why do i get an compile error??
Because it's wrong
The compiler must know the sizes of all the minor dimensions - it's only the left most [] which can be left empty

> lets say a user input the size of the map... how would i achieve that... if we already set the size of the array?
How to dynamically allocate 2D arrays has been discussed many times before - try a board search.