Segmentation fault with a Sieve of Eratosthenes program - c

Question

I'm trying to implement the sieve algorithm where it'll ask for the size of a list of consecutive numbers and print out the prime numbers in that list, but I'm getting a seg fault: 11 error.
This is my code:
#include <stdio.h>
#include <stdlib.h>
#define LIMIT 1000000 /*size of integers array*/
int main(void){
char n[LIMIT];
//Reads the size of integer array
printf("Size of array:\n");
if((fgets(n, LIMIT, stdin)) == NULL) {
fprintf(stderr, "Could not read from stdin\n");
exit(1);
}
unsigned long long int i,j;
int *primes;
int z = 1;
primes = malloc(sizeof(n));
for (i = 2; i < sizeof(n); i++){
primes[i] = 1; //setting every number in list to 1
}
for (i = 2; i < sizeof(n); i++){
if (primes[i]){
for (j = i; (i*j) < sizeof(n); j++){
primes[i * j] = 0; //remove multiples
}
}
}
for (i = 2; i < sizeof(n); i++){
if (primes[i]){
printf("%dth prime = %llu\n",z++,i);
}
}
free(primes);
return 0;
}

Answer 1

char n[LIMIT];
With the value of LIMIT being 1000000, that's a really big array (one million bytes). It would cause stack overflow. You need to dynamically allocate memory for it:
char *n = malloc(LIMIT);

Answer 2

Code is using n in a curious fashion. Suggest simply scanning the the integer n and using n to end the loops rather than sizeof(n).
#include <stdio.h>
#include <stdlib.h>
int main(void){
unsigned long n;
//Reads the size of integer array
buffer[30];
printf("Size of array:\n");
if((fgets(buffer, sizeof buffer, stdin)) == NULL) {
fprintf(stderr, "Could not read from stdin\n");
exit(1);
}
if (sscanf(buffer,"%lu", %n) != 1) {
fprintf(stderr, "Unable to covert to a number\n");
exit(1);
}
unsigned long i,j;
int *primes;
// int z = 1;
primes = malloc(n * sizeof *primes);
for (i = 2; i < n; i++){
primes[i] = 1; //setting every number in list to 1
}
for (i = 2; i < n; i++){
if (primes[i]) {
for (j = i; (i*j) < n; j++){
primes[i * j] = 0; //remove multiples
}
}
}
for (i = 2; i < n; i++){
if (primes[i]){
printf("%dth prime = %llu\n",z++,i);
}
}
free(primes);
return 0;
}