cleanup problem 40 C solution

problem-40.c

@@ -1,19 +1,24 @@
-#include<stdlib.h>
 #include<stdio.h>
+#include<stdlib.h>
 #include<string.h>
 
+
 #define MAX_NUM 1000000
 
-char* LETTERS = "0123456789";
 
-
-int digits(int* res, int num)
+int split_digits(int* digits, int num)
 {
 	int len = 0;
 	while (num > 0) {
 		len++;
-		res = (int*)realloc(res, len * sizeof(int));
-		res[len-1] = num % 10;
+
+		digits = (int*)realloc(digits, len * sizeof(int));
+		if (digits == NULL) {
+			printf("A memory error occurred.\n");
+			exit(1);
+		}
+
+		digits[len-1] = num % 10;
 		num /= 10;
 	}
 
@@ -23,43 +28,38 @@ int digits(int* res, int num)
 
 int main(int argc, char** argv)
 {
-	char* str;
-	int* digs;
-	int nums, j, result;
-	int digit = 0, i = 0, num = 1;
+	int* digits;
+	int len;
+	int digit = 0, i = 0;
+	int prod = 1, num = 1;
 
-	str = malloc(MAX_NUM * sizeof(int));
-	digs = malloc(0 * sizeof(int));
-	nums = digits(digs, num);
+	digits = malloc(0 * sizeof(int));
+	if (digits == NULL) {
+		printf("A memory error occurred.\n");
+		exit(1);
+	}
+
+	len = split_digits(digits, num);
 
 	while (digit < MAX_NUM) {
-		str[digit] = digs[nums-1-i];
+		if (digit == 0 || digit == 9 || digit == 99 || digit == 999
+			|| digit == 9999 || digit == 99999 || digit == 999999)
+			/* Need to step through the array backward */
+			prod *= digits[len-1-i];
+
 		digit++;
 		i++;
-		if (i == nums) {
-			/* refill digs and reset i */
+		if (i == len) {
+			/* refill digits and reset i */
 			num++;
-			nums = digits(digs, num);
 			i = 0;
-			/* DEBUG
-			printf("num = %d str = ", num);
-			for (j=0; j<digit; j++)
-				printf("%d", str[j]);
-			printf("\n");
-			*/
+
+			memset(digits, 0, len * sizeof(int));
+			len = split_digits(digits, num);
 		}
 	}
 
-	result = str[0] *
-		str[9] *
-		str[99] *
-		str[999] *
-		str[9999] *
-		str[99999] *
-		str[999999];
-
-	printf("The result is %d\n", result);
+	printf("The solution is %d\n", prod);
+	free(digits);
 	return 0;
 }
-
-