Shapes and Polymorphism

Lab Python Intermediate 20 points

Create a base class Shape with area() and name, and subclasses Circle(r), Square(s), Triangle(b, h). Read shapes like circle 2 and print name: area with 2 decimals (use π = math.pi).

Input

Line 1: n. Then n shape lines.

Output

n lines.

Example

Input

3
circle 1
square 3
triangle 4 5

Output

circle: 3.14
square: 9.00
triangle: 10.00

Sample input available Sample output available

Editor

Python

Hints

Each subclass overrides area().

A dict can map a word to a class.

Solution explanation

Polymorphism: the loop calls area() without caring which shape it has.

Show solution

import math


class Shape:
    name = "shape"

    def area(self):
        raise NotImplementedError


class Circle(Shape):
    name = "circle"

    def __init__(self, r):
        self.r = r

    def area(self):
        return math.pi * self.r ** 2


class Square(Shape):
    name = "square"

    def __init__(self, s):
        self.s = s

    def area(self):
        return self.s ** 2


class Triangle(Shape):
    name = "triangle"

    def __init__(self, b, h):
        self.b = b
        self.h = h

    def area(self):
        return self.b * self.h / 2


kinds = {"circle": Circle, "square": Square, "triangle": Triangle}
for _ in range(int(input())):
    kind, *nums = input().split()
    shape = kinds[kind](*map(float, nums))
    print(f"{shape.name}: {shape.area():.2f}")

Output

Answer