This document describes a C program created by a group of students to simulate the functions of an ATM machine. The program allows users to enter their PIN and then select from menu options like checking their balance, withdrawing money, depositing money, transferring money, and exiting. Global variables are declared to track the user's balance and PIN attempts. Functions are used to display menus and messages. The main program uses a switch statement to call different functions based on the user's menu selection, and loops to allow multiple transactions per session.