CODEWITHSUNDEEP
pythonclasspython-3.xobject
Madelyn Shroeder
Madelyn Shroeder

Reputation: 21

Object Oriented Python Program calculating volume and Surface area of a sphere

Write a python program that compute the volume and surface area of a sphere with a radius r , a cylinder with a circular base with radius r and height h , and a cone with a circular base with radius r and height h . Place them into a geometry module. Then write a program that prompts the user for the values of r and h , calls the six functions, and prints the results.

Here is my code 

from math import sqrt
from math import pi


# FUNCTIONS
def sphere_volume(radius):
    return 4/3 * pi * (radius ** 3)


def sphere_surface(radius):
    return 4 * pi * radius ** 2


def cylinder_volume(radius, height):
    return pi * radius ** 2


def cylinder_surface(radius, height):
    return pi * radius ** 2 * 2 * pi * radius * height


def cone_volume(radius, height):
    return 1/3 * pi * radius ** 2 * height


def cone_surface(radius, height):
    return pi * radius ** 2 + pi * radius * sqrt(height ** 2 + radius ** 2)


# main
def main():
    radius = input("Radius>")
    height = input("Height>")

    print("Sphere volume: %d" %(sphere_volume(radius)))
    print("Sphere surface: %d" %(sphere_surface(radius)))
    print("Cylinder volume: %d" %(cylinder_volume(radius, height)))
    print("Cylinder surface area: %d" %(cylinder_surface(radius, height)))
    print("Cone volume: %d" %(cone_volume(radius, height)))
    print("Cone surface: %d" %(cone_surface(radius, height)))


# PROGRAM RUN
if __name__ == "__main__":
    main()

I am getting an error 

 return 4/3 * pi * (radius ** 3)

TypeError: unsupported operand type(s) for ** or pow(): 'str' and 'int'

Can someone please help me with what I am doing wrong?

Upvotes: 1

Views: 4036

Answers (2)

DisappointedByUnaccountableMod
DisappointedByUnaccountableMod

Reputation: 6826

What the error message

unsupported operand type(s) for ** or pow(): 'str' and 'int'

means is that the things your code is telling the ** operator to operate on, i.e. radius and 3, aren't compatible with for the ** operator. In particular raising a string (str) to a power doesn't make much sense, does it?

This is because input() returns a string.

To do numeric operations on the value of radius, you have to convert the string to a number. Look at built in function float(), see https://docs.python.org/2/library/functions.html#float and while you're there have a look at some of the other built in functions.

Upvotes: 1

Jason Martinez
Jason Martinez

Reputation: 138

Parse the input like this: 

# main
def main():
    radius = float(input("Radius>"))
    height = float(input("Height>"))

It worked for me.

Upvotes: 5

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