instanceof and Downcasting

In this problem, you will create a program that reads shape data from standard input, checks each element with instanceof, safely downcasts to Circle or Square, and calls type-specific methods, displaying the result to standard output.

Learning Objective: Understand how to safely downcast after checking type with instanceof

Overview

Create a program that reads shape data from standard input, safely downcasts parent type variables to child types, and calls child-specific methods.

Specifications

• Define Shape class and its subclasses (Circle, Square)
• Add getRadius() to Circle, getSide() to Square
• Read shape data from standard input and store in a Shape-type list
• Check each element with instanceof and call appropriate method

Input Format

N
Type1 value1
Type2 value2
...

• Line 1: number of shapes N
• Next N lines: shape type (Circle or Square) and value (decimal) separated by space

Output Format

Circle radius: 5.0
Square side: 4.0
Circle radius: 3.0