diff --git a/src/sort.c b/src/sort.c
index 231b5c0..04d5705 100644
--- a/src/sort.c
+++ b/src/sort.c
@@ -17,6 +17,8 @@
 #include <stdlib.h>
 #include <getopt.h>
 #include <string.h>
+#include <errno.h>
+#include <limits.h>
 #include "random.h"
 #include "timer.h"
 #include "bubble_sort.h"
@@ -27,9 +29,12 @@
 #define SORT_VERSION "1.0.0"
 
 /**
- * El array a ordenar
+ * El array desordenado
  */
 static int *unordered_array;
+/**
+ * El array a ordenar
+ */
 static int *work_array;
 
 /**
@@ -72,30 +77,63 @@ void print_array(int *array, int n) {
  * @return Retorna 1 si es exitosa ó 0 si falla
  */
 int read_buffer(int *variable) {
-	char buffer[12];
+	char buffer[32];
+	char *check;
 	while (1) {
-		if (fgets(buffer, 12, stdin) != NULL) {
+		if (fgets(buffer, 32, stdin) != NULL) {
 			if (buffer[strlen(buffer) - 1] == '\n') {
 				buffer[strlen(buffer) - 1] = '\0';
 				break;
 			}
 		}
 	}
-	char **check = malloc(sizeof(char**));
-	if (check == NULL) {
-		fprintf(stderr, "Error: Out of heap space!\n");
-		exit(5);
+	errno = 0;
+	long input = strtol(buffer, &check, 10);
+	if (buffer == check) {
+		// Empty
+		return 0;
 	}
-	long input = strtol(buffer, check, 10);
-	if (*check[0] == '\0') {
-		free(check);
+	else if (errno == ERANGE && input == LONG_MIN) {
+		// Overflow
+		return 0;
+	}
+	else if (errno == ERANGE && input == LONG_MAX) {
+		// Underflow
+		return 0;
+	}
+	else if (errno == EINVAL) {  /* not in all c99 implementations - gcc OK */
+		// Base contains unsupported value
+		// This check is not in all c99 implementations, but does exist in gcc
+		return 0;
+	}
+	else if (errno != 0 && input == 0) {
+		// Unspecified error
+		return 0;
+	}
+	else if (errno == 0 && !*check) {
+		// Valid number
+		if (input > INT_MAX || input < INT_MIN) {
+			fprintf(stderr, "Error: n tiene que ser menor de 2147483648 y mayor de -2147483649!\n");
+			return 0;
+		}
 		*variable = (int) input;
 		return 1;
 	}
-	else {
-		free(check);
+	else if (errno == 0 && *check != 0) {
+		// Contains non number characters
 		return 0;
 	}
+	else {
+		return 0;
+	}
+}
+
+/**
+ * Imprimir un mensaje y salir si n es invalido
+ */
+void print_invalid_n() {
+	fprintf(stderr, "Error: El valor de n es invalido!\n");
+	exit(7);
 }
 
 /**
@@ -112,7 +150,9 @@ void cleanup() {
  * @return Retorna el codigo de error o 0 por exito
  */
 int main (int argc, char **argv) {
-	long long i;
+	char *check = NULL;
+	long ninput = 0;
+	int i;
 	int n = 10;
 	int elegir = 0;
 	int imprimir = 0;
@@ -173,10 +213,44 @@ int main (int argc, char **argv) {
 				selection = 1;
 				break;
 			case 'n':
-				n = atol(optarg);
-				if (n <= 1) {
-					fprintf(stderr, "Error: n tiene que ser mayor de 1!\n");
-					return 3;
+				errno = 0;
+				ninput = strtol(optarg, &check, 10);
+				if (optarg == check) {
+					// Empty
+					print_invalid_n();
+				}
+				else if (errno == ERANGE && ninput == LONG_MIN) {
+					// Overflow
+					print_invalid_n();
+				}
+				else if (errno == ERANGE && ninput == LONG_MAX) {
+					// Underflow
+					print_invalid_n();
+				}
+				else if (errno == EINVAL) {  /* not in all c99 implementations - gcc OK */
+					// Base contains unsupported value
+					// This check is not in all c99 implementations, but does exist in gcc
+					print_invalid_n();
+				}
+				else if (errno != 0 && ninput == 0) {
+					// Unspecified error
+					print_invalid_n();
+				}
+				else if (errno == 0 && optarg && !*check) {
+					// Valid number
+					if (ninput > INT_MAX || ninput < INT_MIN) {
+						fprintf(stderr, "Error: n tiene que ser menor de 2147483648!\n");
+						return 6;
+					}
+					n = (int) ninput;
+					if (n <= 1) {
+						fprintf(stderr, "Error: n tiene que ser mayor de 1!\n");
+						return 3;
+					}
+				}
+				else if (errno == 0 && optarg && *check != 0) {
+					// Contains non number characters
+					print_invalid_n();
 				}
 				break;
 			case 'e':
@@ -217,15 +291,15 @@ int main (int argc, char **argv) {
 	for (i = 0; i < n; i++) {
 		if (elegir) {
 			opt = 0;
-			fprintf(stdout, "Elegir elemento %lli: ", i + 1);
+			fprintf(stdout, "Elegir elemento %d: ", i + 1);
 			while (!read_buffer(&opt)) {
-				fprintf(stdout, "Número invalido! Tiene que ser mayor de 1!\n");
-				fprintf(stdout, "Elegir elemento %lli: ", i + 1);
+				fprintf(stdout, "Número invalido! Tiene que ser mayor de -2147483649 y menor de 2147483648!\n");
+				fprintf(stdout, "Elegir elemento %d: ", i + 1);
 			}
 			unordered_array[i] = opt;
 		}
 		else {
-			unordered_array[i] = gen_rand((n * 10) * -1, n * 10);
+			unordered_array[i] = gen_rand(-100000000, 100000000);
 		}
 	}