re-formatted code

#vendorInfo.c#

@@ -15,7 +15,7 @@
 #define MAX_VENDORS 20
 #define MAX_FILENAME_LENGTH 4096
 
-/* STRUCTURES */
+/* STRUCTURE DECLARATION */
 typedef struct vendor
 {
 	char vendor_name[20];
@@ -41,8 +41,11 @@ typedef struct purchase_r
 	int price_owe_baht; 
 } purchase_r; 
 
+// The global vendors array
 vendor vendors[MAX_VENDORS];
 
+/* END OF STRUCTURE DECLARATION*/
+
 /* FUNCTION DECLARATION */
 int getstr(char str[], size_t n);
 char *strnlower(char *s, size_t n);
@@ -62,6 +65,7 @@ purchase_r purchase
 );
 
 int check_vendors(vendor vendors[MAX_VENDORS], int total_vendors);
+/* END OF FUNCTION DECLARATION */
 
 int main()
 {
@@ -72,8 +76,8 @@ int main()
 	FILE *fp;
 	if ((fp = fopen(file_name, "r")) == NULL) 
 	{
-		printf("%s cannot be opened.\n", file_name);
+		perror("Error opening file");
-		exit(EXIT_FAILURE);
+		return 1; 
 	}
 
 	// Calculate the file size
@@ -83,10 +87,14 @@ int main()
 
 	// Dynamically allocate buffer for file content
 	char *file_buffer = (char *) malloc(file_size);
-	int index = 0;
+	int index = 0; // The index for the while loop below. 
 
 	// Reading the file with fgets and formatting them using strtok
-	while ((fgets(file_buffer, 50, fp) != NULL) && (index <= MAX_VENDORS - 1))
+	while
+	(
+		(fgets(file_buffer, 50, fp) != NULL) &&
+		(index <= MAX_VENDORS - 1)
+	)
 	{
 		char *token = strtok(file_buffer, " ");
 		strncpy(vendors[index].vendor_name, token, strlen(token) + 1); 
@@ -103,9 +111,15 @@ int main()
 		index++;	
 	}
 
+	// Error handling 
 	if (ferror(fp))
 	{
-	  printf("");
+		perror("An error occured while reading the file.\n");
+
+		fclose(fp);
+		free(file_buffer);
+
+		return 1; 
 	}
 
 	int total_vendors = index;
@@ -125,7 +139,11 @@ int main()
 	    */
 		for (int j = i + 1; j < total_vendors; j++)
 		{
-			if ((strcmp(vendors[i].merchandise, vendors[j].merchandise)) == 0) 
+			if (
+				(strcmp(vendors[i].merchandise,
+						vendors[j].merchandise)
+					)
+				== 0) 
 			{
 				vendors[j].duplicate = 1;
 			}
@@ -185,11 +203,12 @@ int main()
 		}
 		else
 		{
-			// convert string to lowercase - each character one by one
 			int user_query_length = strlen(user_query);	
 			strnlower(user_query, user_query_length);
 			
-			struct search_r item = search(user_query, vendors, total_vendors);
+			struct search_r item = search(user_query,
+										  vendors,
+										  total_vendors);
 			if(item.status == 0)
 			{
 				char input[10];
@@ -197,13 +216,12 @@ int main()
 				printf("How many do you want to buy? ");
 				getstr(input, 10);
 				  
-				// If a character of a string was sent, the return value would always be 0
+				if(atoi(input) > 0)    // atoi returns 0 if character was sent 
-				// If a negative number was sent, the return value will always be negative.
+				{                      // atoi returns -x if -x was provided
-				
-				if(atoi(input) > 0) 
-				{
 					int item_amount = atoi(input);
-					purchase_r response = purchase(item.item_id, item_amount, vendors);
+					purchase_r response = purchase(item.item_id,
+												   item_amount,
+												   vendors);
 
 					if (response.status == 0)
 					{
@@ -224,7 +242,8 @@ int main()
 				else 
 				{
 					printf("\e[31m%s\e[m\n",
-						   "You must enter a positive whole number for the number of items"
+						   "You must enter a positive whole number"
+						   " for the number of items"
 					);                      	
 				}
 
@@ -232,7 +251,8 @@ int main()
 			else if (item.status == 2)
 			{
 				printf("\e[31m%s\e[m\n",
-					   "This item has duplicate records, please choose another item"
+					   "This item has duplicate records,"
+					   " please choose another item"
 				);
 			}
 			else
@@ -277,9 +297,14 @@ int main()
 
 	Parameters: 
 	    - str = string itself
-	    - n = max amount of characters that the function is able to read into buffer
+	    - n = max amount of characters that the function
+		      is able to read into buffer
 
-	Reads one character at a time into buffer and adds a null terminator when finish reading
+	Reads one character at a time into buffer
+	and adds a null terminator when finish reading
+
+	Return values:
+	     - (int) i: length of string
 */
 int getstr(char str[], size_t n) 
 {
@@ -325,9 +350,9 @@ char *strnlower(char *s, size_t n)
 
 	Return values:
 	    (search_r) response:
-	    - status: 0 (Found item)
+	    - status: 0 (Found record) + id of record
 		- status: 1 (No results)
-		- status: 2 (Found duplicate item)
+		- status: 2 (Found duplicate record)
 */
 
 search_r search(char query[], vendor vendors[MAX_VENDORS], int total_vendors)
@@ -376,6 +401,7 @@ search_r search(char query[], vendor vendors[MAX_VENDORS], int total_vendors)
 	Return values:
 	    (purchase_r) response:
 	    - status: 0 (Purchase successful)
+		          Also includes the vendor_name, price owe and revenue
 		- status: 1 (Vendor does not have enough items)
 */
 
@@ -423,7 +449,8 @@ int check_vendors(vendor vendors[MAX_VENDORS], int total_vendors)
 	int i;
 	for (i = 0; i < total_vendors; i++)
 	{
-		// Condition: Vendors that are not empty (Check if not marked as duplicates) 
+		// Condition: Vendors that are not empty
+		// (only ones that are not duplicates) 
 		if (vendors[i].inventory_count != 0 && vendors[i].duplicate == 0)
 		{
 			return 1;
@@ -435,3 +462,4 @@ int check_vendors(vendor vendors[MAX_VENDORS], int total_vendors)
 		return 0;
 	}
 };
+;

vendorInfo.c

@@ -15,7 +15,7 @@
 #define MAX_VENDORS 20
 #define MAX_FILENAME_LENGTH 4096
 
-/* STRUCTURES */
+/* STRUCTURE DECLARATION */
 typedef struct vendor
 {
 	char vendor_name[20];
@@ -41,8 +41,11 @@ typedef struct purchase_r
 	int price_owe_baht; 
 } purchase_r; 
 
+// The global vendors array
 vendor vendors[MAX_VENDORS];
 
+/* END OF STRUCTURE DECLARATION*/
+
 /* FUNCTION DECLARATION */
 int getstr(char str[], size_t n);
 char *strnlower(char *s, size_t n);
@@ -62,6 +65,7 @@ purchase_r purchase
 );
 
 int check_vendors(vendor vendors[MAX_VENDORS], int total_vendors);
+/* END OF FUNCTION DECLARATION */
 
 int main()
 {
@@ -73,7 +77,7 @@ int main()
 	if ((fp = fopen(file_name, "r")) == NULL) 
 	{
 		perror("Error opening file");
-		exit(EXIT_FAILURE);
+		return 1; 
 	}
 
 	// Calculate the file size
@@ -83,10 +87,14 @@ int main()
 
 	// Dynamically allocate buffer for file content
 	char *file_buffer = (char *) malloc(file_size);
-	int index = 0;
+	int index = 0; // The index for the while loop below. 
 
 	// Reading the file with fgets and formatting them using strtok
-	while ((fgets(file_buffer, 50, fp) != NULL) && (index <= MAX_VENDORS - 1))
+	while
+	(
+		(fgets(file_buffer, 50, fp) != NULL) &&
+		(index <= MAX_VENDORS - 1)
+	)
 	{
 		char *token = strtok(file_buffer, " ");
 		strncpy(vendors[index].vendor_name, token, strlen(token) + 1); 
@@ -106,7 +114,12 @@ int main()
 	// Error handling 
 	if (ferror(fp))
 	{
-		printf("An error occured while reading the file.\n");
+		perror("An error occured while reading the file.\n");
+
+		fclose(fp);
+		free(file_buffer);
+
+		return 1; 
 	}
 
 	int total_vendors = index;
@@ -126,12 +139,15 @@ int main()
 	    */
 		for (int j = i + 1; j < total_vendors; j++)
 		{
-			if ((strcmp(vendors[i].merchandise, vendors[j].merchandise)) == 0) 
+			if (
+				(strcmp(vendors[i].merchandise,
+						vendors[j].merchandise)) == 0) 
 			{
 				vendors[j].duplicate = 1;
 			}
 			
-			if ((strcmp(vendors[i].vendor_name, vendors[j].vendor_name)) == 0)
+			if ((strcmp(vendors[i].vendor_name,
+						vendors[j].vendor_name)) == 0)
 			{
 				vendors[j].duplicate = 1;
 			}
@@ -186,11 +202,12 @@ int main()
 		}
 		else
 		{
-			// convert string to lowercase - each character one by one
 			int user_query_length = strlen(user_query);	
 			strnlower(user_query, user_query_length);
 			
-			struct search_r item = search(user_query, vendors, total_vendors);
+			struct search_r item = search(user_query,
+										  vendors,
+										  total_vendors);
 			if(item.status == 0)
 			{
 				char input[10];
@@ -198,13 +215,12 @@ int main()
 				printf("How many do you want to buy? ");
 				getstr(input, 10);
 				  
-				// If a character of a string was sent, the return value would always be 0
+				if(atoi(input) > 0)    // atoi returns 0 if character was sent 
-				// If a negative number was sent, the return value will always be negative.
+				{                      // atoi returns -x if -x was provided
-				
-				if(atoi(input) > 0) 
-				{
 					int item_amount = atoi(input);
-					purchase_r response = purchase(item.item_id, item_amount, vendors);
+					purchase_r response = purchase(item.item_id,
+												   item_amount,
+												   vendors);
 
 					if (response.status == 0)
 					{
@@ -225,7 +241,8 @@ int main()
 				else 
 				{
 					printf("\e[31m%s\e[m\n",
-						   "You must enter a positive whole number for the number of items"
+						   "You must enter a positive whole number"
+						   " for the number of items"
 					);                      	
 				}
 
@@ -233,7 +250,8 @@ int main()
 			else if (item.status == 2)
 			{
 				printf("\e[31m%s\e[m\n",
-					   "This item has duplicate records, please choose another item"
+					   "This item has duplicate records,"
+					   " please choose another item"
 				);
 			}
 			else
@@ -278,9 +296,14 @@ int main()
 
 	Parameters: 
 	    - str = string itself
-	    - n = max amount of characters that the function is able to read into buffer
+	    - n = max amount of characters that the function
+		      is able to read into buffer
 
-	Reads one character at a time into buffer and adds a null terminator when finish reading
+	Reads one character at a time into buffer
+	and adds a null terminator when finish reading
+
+	Return values:
+	     - (int) i: length of string
 */
 int getstr(char str[], size_t n) 
 {
@@ -326,9 +349,9 @@ char *strnlower(char *s, size_t n)
 
 	Return values:
 	    (search_r) response:
-	    - status: 0 (Found item)
+	    - status: 0 (Found record) + id of record
 		- status: 1 (No results)
-		- status: 2 (Found duplicate item)
+		- status: 2 (Found duplicate record)
 */
 
 search_r search(char query[], vendor vendors[MAX_VENDORS], int total_vendors)
@@ -377,6 +400,7 @@ search_r search(char query[], vendor vendors[MAX_VENDORS], int total_vendors)
 	Return values:
 	    (purchase_r) response:
 	    - status: 0 (Purchase successful)
+		          Also includes the vendor_name, price owe and revenue
 		- status: 1 (Vendor does not have enough items)
 */
 
@@ -424,7 +448,8 @@ int check_vendors(vendor vendors[MAX_VENDORS], int total_vendors)
 	int i;
 	for (i = 0; i < total_vendors; i++)
 	{
-		// Condition: Vendors that are not empty (Check if not marked as duplicates) 
+		// Condition: Vendors that are not empty
+		// (only ones that are not duplicates) 
 		if (vendors[i].inventory_count != 0 && vendors[i].duplicate == 0)
 		{
 			return 1;