#This program will ask for a shape and 
#calculate the area and perimeter

import math

print("Select a shape:")
print("1. Square")
print("2. Rectangle")
print("3. Circle")
print("4. Hexagon")
print("5. Decagon")
keep_going = ""

while keep_going == "":
        
    shape = input("Choose a number from 1-5. ")

    if shape == "1":
        print("You chose square.")
        square_side = float(input("Enter the length of a side: "))
        if square_side < 0:
                raise ValueError("Side length cannot be negative.")
        
            
        square_area = side **2
        square_perimeter = side * 4
        print(f"The perimeter of a square with a length of {side} is {square_perimeter}.\n"
          f"The area is {square_area}.")
    elif shape == "2":
        print("You chose rectangle.")
        length = float(input("Enter the length of a side: "))
        width = float(input("Enter the length of another side: "))
        if length or width < 0:
                raise ValueError("Side length cannot be negative.")
        
        
    
        rectangle_area = length * width
        rectangle_perimeter = 2 * (length + width)

        print(f"The perimeter of a rectangle with a length of {length} and a width of {width} is {rectangle_perimeter}.\n"
              f"The area is {rectangle_area}.")
    elif shape == "3":
        print("You chose circle.")
        radius = float(input("Enter the length of the radius: "))
        if radius < 0:
                raise ValueError("radius length cannot be negative.")
        
            
    
        circle_area = 3.14159 * (radius ** 2) 
        circle_circumference = 2 * 3.14159 * radius
        
        print(f"The circumference of a circle with a radius of {radius} is {circle_circumference}.\n"
              f"The area is {circle_area}.")
        

    elif shape == "4":
        print("You chose hexagon.")
        hexagon_side = float(input("Enter the length of the side: "))
        def hexagon_area(hexagon_side):
            if hexagon_side < 0:
                raise ValueError("Side length cannot be negative.")
        
            return (3 * math.sqrt(3) / 2) * (hexagon_side ** 2)
        area = hexagon_area(hexagon_side)
        hexagon_perimeter = hexagon_side * 6

        print(f"The area of a hexagon with a length of {hexagon_side} is {area:.2f}.\n"
              f"The perimeter is {hexagon_perimeter:.2f}.")

    elif shape == "5":
        print("You chose decagon.")
        decagon_side = float(input("Enter the length of the side: "))

        def decagon_area(decagon_side):
            """Calculates the area of a regular decagon given its side length."""
            if decagon_side < 0:
                raise ValueError("Side length cannot be negative.")
        
            constant_part = math.sqrt(5 + 2 * math.sqrt(5))
            area = (5 / 2) * (decagon_side ** 2) * constant_part
            return area

        area = decagon_area(decagon_side)
        perimeter = 10 * decagon_side

        print(f"The area of a decagon with a length of {decagon_side} is {area}.\n"
              f"The perimeter is {perimeter:.2f}.")
    
              
    else:  
        print("You entered an invalid option.")

    keep_going = input("Press enter to keep calculating, or type anything else to exit. ")
    if keep_going != "":
        print(f"Time to study!")

print("This program has ended")