It is a food delivery application Firstly in the main method the user is asked to eneter a choice(a number out of 1,2,3) according to his/her needs CASE 1 is for registering a restaurant CASE 2 is for creating a new customer account if he/she has logged in for the first time CASE 3 is for placing the order(the user already has an account) If the user selects 1 Method register_restaurant is called In register_restaurant() Inputs taken from user=name of restaurant,number of items Input stored in name,limit variable respectively Then fstream object created fout Restaurant.csv file opened Store the restaurant name stored in"name" in the csv file Then create a csv file with the name same as the restaurant name Start a loop from i=0 to i<limit Take the name and price of each item and store in "itemname","price" respectively Close the file Fout.close(); A message is displayed on screen-"do you wish to continue" You can type either T or F for yes/no Like this you can register many restaurants and all the restaurant name will be saved in restaurant.csv The menu of a particular restaurant will be saved it its seperate csv file I have alredy registered 4 restaurants-kfc,dominos,keventers,baskin as can be seen in restaurant.csv file uploaded here The menu of a particular restaurant can be viewed in the csv file of tha particular restaurant Tf the user selects 2 Method register_customer() is called In this method fstream object f created customer_Login_Details.csv file opened Inputs take-name,password,phone number Inputs stored in variable=name,password,ph Then is_registered method called Tn is_registered(long long ph) ph in long long is converted to sting and stored in "num" using stream.str() ifstream object ip created Open file customer_Login_Details.csv Start a while loop Each phone number in this csv file is stored in phone Compare phone and num and store the result in x x=0 if the number matches if x=0 The users has alresdy registered with this number return 1 else return 0 Now in register_customer() if (!(is_registered(ph))) Store the name,phone no,.password in customer_Login_Details.csv If the user selects 3 login() method called Inputs taken=phone,password Inputs stored in =ph,pass customer_login() method is called to get the name for this particular phone number In customer_login(long long ph,string pass) ph converted to string and stored in"num" ifstream object ip created Open file customer_Login_Details.csv Read name,phone and password from file and store in "nm","phone","password" Compare each ph no. and password with the entered ph no. and password if (num.compare(phone) == 0 && pass.compare(password) == 0) return nm else return"\0" in login() The name retured by customer_login is stored in "name" User is asked to eneter a choice(a number out of 1,2,3) according to his/her needs CASE1 is for viewing order history CASE2 is for placing order If 2 is selected Method place_order(ph,name) is called In place_order(long long ph,string name) Select_restuarent () is called In select_restaurent() ifstream object fout created open file restaurents.csv Display all the restaurant Store the restaurant eneterd by the user in "res_name" ifstream object fout created Open file order.csv Start a while loop for reading this file int ctr;//ctr is acounter variable for tracking live orders are not more than 10 while (ff.good()) Store restauarant name of each order in "rest" and status in "status" Compare "res_name"with"status" and increas ctr by everytime it matches Finally check if (ctr>10) Ff yes return "NULL" else return res_name to place_order() In place_order() Returned string from select_restaurent() is stored in rest_name if (rest_name.compare("NULL") == 0) The below message is printed cout << "SORRY !!! THIS RESTAURANT IS NOT ACCEPTING ORDERS FOR NOW " << endl; else ifstream object fout created Open csv file of that particular restaurant Display menu of that file Input form the use= number of items(stored in varuable sizee),name of items(stored in array arr of size "size" All items are then stores in array using while loop str=string which is combination of all the items in one seperated by'-' generte_bill () method called In genertare_bill(string arr[], string name, int size) Inputs taken are 1-an array consisting of all the items ordered by the user 2-name of the restaurant 3-size of the array for loop form int i=0 to size ifstream object fout created Open file of this restaurant Read this file using while loop while (fout.good()) Store each item on menu and its price in"item"and "price" variable food_name stores element of the arra at index i Compare item and food_name item.compare(food_name) == 0 if matched bill = bill + stof(price); return bill; The retured amount is stored in"bill" fstream object fin created open file order.csv Store name,phone,restaurant,order,bill,status in order.csv close fin fin.close(); if 1 is selected order_history() method called fstream object f created open file order.csv Print "DISPLAYING ORDER HISTORY " Compare each number of order.csv with enterd number if match found Store resataurant ,order,bil in variables "rest","order_name","bill" Display detaiils in format restaurant name: items orders: total bill: close f If the user gives a wrong input "wrong choice " printed