LAB Activity(practice only 4-Programs) 1- A program that takes a four digits integer from user and shows the digits on the screen separately i.e. if user enters 7531, it displays 1357 separately. 2- A program takes the radius of a circle from the user and calculates the diameter, circumference and area of the circle and displays the result. 3- This program gets a grade from user and displays a description accordingly. 4- This program calculates the square of a given number.