Interface for geometric shapes

Go Easy interfaces

Task «Interface for geometric shapes»

Create a Shape interface that contains the Area() float64 method. Implement the Circle (with a Radius float64 field) and Rectangle (with Width, Height float64 fields) structs that satisfy the Shape interface. Write a PrintArea(s Shape) function that prints the area of the shape with an accuracy of two decimal places. In main, read from stdin a string containing the shape type ('circle' or 'rectangle') and its parameters (radius for a circle, width and height for a rectangle). Call PrintArea for the corresponding shape.

Input Format

One line: first the word 'circle' or 'rectangle', then numbers (for circle — radius, for rectangle — width and height). All numbers are integers or floating-point.

Output Format

One number — the area of the figure, rounded to two decimal places.

Examples

Example 1

INPUT

circle 5

OUTPUT

78.54

Example 2

INPUT

7
ADD 1 handler1
ADD 1 handler2
FIRE 1 eventA
ADD 2 handler3
FIRE 1 eventB
REMOVE 1 handler1
FIRE 1 eventC

OUTPUT

Example 3

INPUT

rectangle 3 4

OUTPUT

12.00

Example 4

INPUT

5
ADD 5 procA
ADD 5 procB
FIRE 5 data1
REMOVE 5 procA
FIRE 5 data2

OUTPUT

Example 5

INPUT

circle 0

OUTPUT

0.00

main.go