Print elements of array between other output in C

Question

I am trying to print results of my sudoku solving program into terminal like this:

  +-------+-------+-------+
  | 1 2 3 | 4 5 6 | 7 8 9 |
  | 1 2 3 | 4 5 6 | 7 8 9 |
  | 1 2 3 | 4 5 6 | 7 8 9 |
  +-------+-------+-------+
  | 1 2 3 | 4 5 6 | 7 8 9 |
  | 1 2 3 | 4 5 6 | 7 8 9 |
  | 1 2 3 | 4 5 6 | 7 8 9 |
  +-------+-------+-------+
  | 1 2 3 | 4 5 6 | 7 8 9 |
  | 1 2 3 | 4 5 6 | 7 8 9 |
  | 1 2 3 | 4 5 6 | 7 8 9 |
  +-------+-------+-------+

I store my solution in one dimensional array and I cannot find a way to print it. This is what I came up with so far:

printf("| %c %c %c | %c %c %c | %c %c %c |\n", test[0],test[1],test[2],test[3],test[4],test[5],test[6],test[7],test[8]);

I cannot use any cycles because I need to draw the "walls" around the numbers. Is there any better way to do it? And why does

char test[] = {'1','2','3','4','5','6','7','8','9'};
int i = 0;
printf("| %c %c %c | %c %c %c | %c %c %c |\n",   test[i++],test[i++],test[i++],test[i++],test[i++],test[i++],test[i++],test[i++],test[i++]);

returns | 9 8 7 | 6 5 4 | 3 2 1 | Thanks.

is it a multidimensional array? which part you feel it's difficult for you? — Jason Hu
– Jason Hu, Commented Aug 29, 2015 at 14:59
i can tell you are using gcc by reading the evaluation order. why do you say you can't use a loop? think it twice. that's not true. — Jason Hu
– Jason Hu, Commented Aug 29, 2015 at 15:01
It is one dimensional array. I don't know how can I use loops since I print three numbers and then the | character. And there are the +-----+-----+ lines. I can print the picture above with hard coded numbers but I don't know how to put numbers from my array there — Milda
– Milda, Commented Aug 29, 2015 at 15:07
replace this kind of line: printf("| %c %c %c | %c %c %c | %c %c %c |\n", test[i++],test[i++],test[i++],test[i++],test[i++],test[i++],test[i++],test[i++],test[i++]); with printf("| %c %c %c | %c %c %c | %c %c %c |\n", test[i],test[i+1],test[i+2],test[i+3],test[i+4],test[i+5],test[i+6],test[i+7],test[i+8]); i+=9; — user3629249
– user3629249, Commented Aug 30, 2015 at 15:14

melpomene · Accepted Answer · 2015-08-29 15:20:33Z

5

Here's one way to decompose this into (nested) loops:

void print_data_row(const char *p) {
    printf("|");
    for (int i = 0; i < 3; i++) {
        for (int j = 0; j < 3; j++) {
            printf(" %c", p[i*3 + j]);
        }
        printf(" |");
    }
    printf("\n");
}

void print_separator(void) {
    printf("+-------+-------+-------+\n");
}

...
print_separator();
for (int i = 0; i < 3; i++) {
    for (int j = 0; j < 3; j++) {
        print_data_row(&board[(i*3 + j) * 9]);
    }
    print_separator();
}

edited Aug 29, 2015 at 15:20

answered Aug 29, 2015 at 15:17

melpomene

86.2k8 gold badges97 silver badges156 bronze badges

Sign up to request clarification or add additional context in comments.

3 Comments

Milda Over a year ago

Thanks, this is exactly what I was looking for. I tried a similar approach but couldn't get the incrementation right and when I did, it seemed too complicated so I just tried the non-loop version. Does that mean that there isn't any simpler way to do this in C? Something like printf("%c %c %c", array of elements to print); ?

melpomene Over a year ago

@Milda You can't automatically "expand" an array to a list of function arguments. You can of course pass each element separately: printf("%c %c %c", array[i], array[i + 1], array[i + 2]);

Milda Over a year ago

That was basically why I asked this question. I fixed my nested-loops version (forgot to add j in one loop) and it works perfectly now. Thanks

AdminXVII · Accepted Answer · 2015-08-29 15:36:09Z

1

Try this:

for(int i = 0; i < 13; i++){ // 13 because 9 numbers + 4 separators
  for(int j = 0; i < 13; i++){
    if((i % 4 == 0) && (j % 4 == 0)){
      printf("+"); // separator crossing
    } else if (i % 4 == 0){
      printf("-"); // vertical separator
    } else if (j % 4 == 0){
      printf("|"); // horizontal separator
    } else {
      printf("%d",sudoku[row(i)][row(j)]); // sudoku is the 2d result array
    }
  printf("\n"); // end of line
}

int row(j){ // row (or column) without counting separators
  int nOfSeparator = (i - (i % 4))/4;
  return (13 - nOfSeparator);
}

answered Aug 29, 2015 at 15:36

AdminXVII

1,32911 silver badges23 bronze badges

Comments

Jens · Accepted Answer · 2015-08-30 15:39:24Z

1

No loops? Ok. I'd be inclined to say this is even a superior solution compared to a single or nested loop. It can be seen to do what it is supposed to do.

char *t = test;
printf("+-------+-------+-------+\n");
printf("| %c %c %c | %c %c %c | %c %c %c |\n", t[0],t[1],t[2],t[3],t[4],t[5],t[6],t[7],t[8]);
t += 9;
printf("| %c %c %c | %c %c %c | %c %c %c |\n", t[0],t[1],t[2],t[3],t[4],t[5],t[6],t[7],t[8]);
t += 9;
printf("| %c %c %c | %c %c %c | %c %c %c |\n", t[0],t[1],t[2],t[3],t[4],t[5],t[6],t[7],t[8]);
t += 9;
printf("+-------+-------+-------+\n");
printf("| %c %c %c | %c %c %c | %c %c %c |\n", t[0],t[1],t[2],t[3],t[4],t[5],t[6],t[7],t[8]);
t += 9;
printf("| %c %c %c | %c %c %c | %c %c %c |\n", t[0],t[1],t[2],t[3],t[4],t[5],t[6],t[7],t[8]);
t += 9;
printf("| %c %c %c | %c %c %c | %c %c %c |\n", t[0],t[1],t[2],t[3],t[4],t[5],t[6],t[7],t[8]);
t += 9;
printf("+-------+-------+-------+\n");
printf("| %c %c %c | %c %c %c | %c %c %c |\n", t[0],t[1],t[2],t[3],t[4],t[5],t[6],t[7],t[8]);
t += 9;
printf("| %c %c %c | %c %c %c | %c %c %c |\n", t[0],t[1],t[2],t[3],t[4],t[5],t[6],t[7],t[8]);
t += 9;
printf("| %c %c %c | %c %c %c | %c %c %c |\n", t[0],t[1],t[2],t[3],t[4],t[5],t[6],t[7],t[8]);
printf("+-------+-------+-------+\n");

edited Aug 30, 2015 at 15:39

answered Aug 29, 2015 at 15:26

Jens

73.3k16 gold badges134 silver badges186 bronze badges

1 Comment

Milda Over a year ago

Thanks, this is something I ended up with.I was just looking for something like printf("%c %c %c", array of elements to print) so I wouldn't have to use nested loops since it seemed too complicated (and therefore wrong) to me.

Community · Accepted Answer · 2017-05-23 11:52:09Z

1

Q. Is there any better way to do it?
A. Try using loops to achieve the same.

For your second question, the answer is that the order of evaluation of function parameters is not certain in C. Hence, you never know, which of those nine test[i++] gets evaluated first. Hence, the unknown result (undefined behavior actually). More here.

edited May 23, 2017 at 11:52

CommunityBot

11 silver badge

answered Aug 29, 2015 at 14:59

CinCout

9,63916 gold badges55 silver badges74 bronze badges

1 Comment

melpomene Over a year ago

It's not just an unknown result. Modifying the same variable twice (without a sequence point in between) has undefined behavior.

Collectives™ on Stack Overflow

Print elements of array between other output in C

4 Answers 4

3 Comments

Comments

1 Comment

1 Comment

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

4 Answers 4

3 Comments

Comments

1 Comment

1 Comment

Your Answer

Sign up or log in

Post as a guest

Linked

Related