Given a text file containing the availability of food items, write a program that reads the information from the text file and outputs the available food items. The program should first read the name of the text file from the user. The program then should read the text file, line by line. If a food is available, the program should output the available food item in the following format: name (category) -- description
Assume the text file contains the category, name, description, and availability of at least one food item, separated by a tab character ('\t').
Hints: Use the find() function to find the index of a tab character in each row of the text file. Use the substr() function to extract the text separated by the tab characters.