This is a demo of 2D arrays in C written for my (imaginary) friend.

array2d.c

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

int main(int argc, char const *argv[])
{
	int **array2d, n, i, j;

	puts("Enter a number:");
	scanf("%d", &n);
	puts("Thank you, kind sir.");

	if (n < 1) {
		puts("Go away, I hate you.");
		return 9;
	}

	// Init:

	array2d = malloc(n * sizeof(*array2d)); // int *

	for (i = 0; i < n; ++i) {
		array2d[i] = malloc(n * sizeof(**array2d)); // int
	}

	// Usage:

	for (i = 0; i < n; ++i) {
		for (j = 0; j < n; ++j) {
			array2d[i][j] = (i + 1) * (j + 1);
		}
	}

	for (i = 0; i < n; ++i) {
		for (j = 0; j < n; ++j) {
			printf("%3d ", array2d[i][j]);
		}
		puts(""); // newline
	}

	return 0;
}