added purchase function

vendorInfo.c

@@ -88,6 +88,14 @@ int main()
 	char user_query[100];
 	read_input(user_query, 100);
 	
+	while (1) 
+	{
+		if ((strcmp(user_query, "DONE") == 0)) 
+		{
+			break;
+		}
+
+		read_input(user_query, 100);
 		// convert string to lowercase - each character one by one
 		int user_query_length = strlen(user_query);	
 		for (int i = 0; i < user_query_length; i++)
@@ -96,6 +104,7 @@ int main()
 		};
 
 		search(user_query, vendors, total_vendors);
+	}
 		
 	fclose(fp);
 	free(file_buffer);
@@ -132,6 +141,10 @@ int read_input(char str[], int n)
 		- query: search query
 		- vendors: the vendor table
 		- total_vendors: the amount of vendors
+
+	Return values:
+		- i: Item Number
+		- 0: No results found
 */
 int search(char query[], struct vendor_item vendors[MAX_VENDORS], int total_vendors)
 {
@@ -145,27 +158,37 @@ int search(char query[], struct vendor_item vendors[MAX_VENDORS], int total_vend
 				vendors[i].vendor_name, 
 				vendors[i].merchandise
 			);
+			return i;
 			break;	
 		};
 	};
 
 	if (i == total_vendors)
 	{
-		printf("No results found - %d\n", i);
-	}
-	
 		return 0;
+	}
 };
 
 /* 
 	Purchase function
 
 	Parameters:
-		- item: The item that the user is purchasing
+		- item_id: The item id that the user is purchasing
 		- amount: How many items that the user is purchasing
 		- vendors: vendor table
-*/
-int purchase(char item[], int amount, struct vendor_item vendors[MAX_VENDORS])
-{
 
+	Return values:
+		- 
+*/
+int purchase(int item_id, int amount, struct vendor_item vendors[MAX_VENDORS])
+{
+	if(amount <= vendors[item_id].inventory_count)
+	{
+		vendors[item_id].inventory_count = vendors[item_id].inventory_count - amount;
+		return vendors[item_id].inventory_count;
+	}
+	else
+	{
+		return 0;
+	} 
 };