How can I print an array like a grid? - c

Question

Hello I'm new at programming and I need to print an array (must be 1 dimensionnal) like a grid. I tried for hours now and still don't have the results I want.
The array has 16 values so the grid would be something like this :
___________
|0 |1 |2 |3 |
|4 |5 |6 |7 |
|8 |9 |10|11|
|12|13|14|15|
–––––––––––––
My code :
#include <stdio.h>
void display_grid(void)
{
int i;
int j;
int cell[16] = {0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15};
for (i = 0; i < 4; i++)
{
printf("|");
for (j = 0; j < 16; j++)
{
printf("%d|",cell[j]);
}
printf("\n");
}
}
int main()
{
display_grid();
return 0;
}
Displays this :
|0|1|2|3|4|5|6|7|8|9|10|11|12|13|14|15|
|0|1|2|3|4|5|6|7|8|9|10|11|12|13|14|15|
|0|1|2|3|4|5|6|7|8|9|10|11|12|13|14|15|
|0|1|2|3|4|5|6|7|8|9|10|11|12|13|14|15|

Answer 1

I have a feeling that this would work: I changed cell[j] to cell[4 * i + j]
#include <stdio.h>
void display_grid(void)
{
int i;
int j;
int cell[16] = {0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15};
for (i = 0; i < 4; i++)
{
printf("|");
for (j = 0; j < 4; j++)
{
printf("%d|",cell[4 * i + j]);
}
printf("\n");
}
}
int main()
{
display_grid();
return 0;
}
Does this help?

Answer 2

You can use the remainder operator % to determine when to print on a new line. Here is an example program with a display_grid() function that takes as arguments an array of int, the size of the array, and the desired size of each row. If the array can be evenly divided into rows of the desired number of columns, zero is returned. Otherwise a non-zero value is returned. This allows you to display a 1d array in various grid formats; nothing is printed if the array can't be evenly divided.
Currently this prints grids containing numbers with at most 2 digits (or 1 digit and a sign). It would be simple to modify it to print more digits, or a little more involved to modify so that the display width fits the maximum width needed for the input.
#include <stdio.h>
#define ARR_SZ 16
int display_grid(int *arr, size_t arr_sz, size_t row_sz);
int main(void)
{
int array[ARR_SZ];
for (size_t i = 0; i < ARR_SZ; i++) {
array[i] = i;
}
size_t row_sz = 4;
if (display_grid(array, ARR_SZ, row_sz) != 0) {
fprintf(stderr, "Array size not evenly divisible by %zu\n", row_sz);
}
row_sz = 8;
if (display_grid(array, ARR_SZ, row_sz) != 0) {
fprintf(stderr, "Array size not evenly divisible by %zu\n", row_sz);
}
row_sz = 2;
if (display_grid(array, ARR_SZ, row_sz) != 0) {
fprintf(stderr, "Array size not evenly divisible by %zu\n", row_sz);
}
row_sz = 1;
if (display_grid(array, ARR_SZ, row_sz) != 0) {
fprintf(stderr, "Array size not evenly divisible by %zu\n", row_sz);
}
row_sz = 16;
if (display_grid(array, ARR_SZ, row_sz) != 0) {
fprintf(stderr, "Array size not evenly divisible by %zu\n", row_sz);
}
row_sz = 6;
if (display_grid(array, ARR_SZ, row_sz) != 0) {
fprintf(stderr, "Array size not evenly divisible by %zu\n", row_sz);
}
row_sz = 32;
if (display_grid(array, ARR_SZ, row_sz) != 0) {
fprintf(stderr, "Array size not evenly divisible by %zu\n", row_sz);
}
return 0;
}
int display_grid(int *arr, size_t arr_sz, size_t row_sz)
{
int ret_val = arr_sz % row_sz;
if (ret_val == 0) {
/* Print top border */
putchar(' ');
for (size_t i = 1; i < 3 * row_sz; i++) {
putchar('_');
}
putchar('\n');
/* Print rows of grid */
for (size_t i = 0; i < arr_sz; i++) {
printf("|%-2d", arr[i]);
if ((i + 1) % row_sz == 0) {
printf("|\n");
}
}
/* Print bottom border */
for (size_t i = 0; i < 3 * row_sz + 1; i++) {
putchar('-');
}
putchar('\n');
}
return ret_val;
}
Program output:
___________
|0 |1 |2 |3 |
|4 |5 |6 |7 |
|8 |9 |10|11|
|12|13|14|15|
-------------
_______________________
|0 |1 |2 |3 |4 |5 |6 |7 |
|8 |9 |10|11|12|13|14|15|
-------------------------
_____
|0 |1 |
|2 |3 |
|4 |5 |
|6 |7 |
|8 |9 |
|10|11|
|12|13|
|14|15|
-------
__
|0 |
|1 |
|2 |
|3 |
|4 |
|5 |
|6 |
|7 |
|8 |
|9 |
|10|
|11|
|12|
|13|
|14|
|15|
----
_______________________________________________
|0 |1 |2 |3 |4 |5 |6 |7 |8 |9 |10|11|12|13|14|15|
-------------------------------------------------
Array size not evenly divisible by 6
Array size not evenly divisible by 32