my first calculator thingy

project_x.py

import decimal
# version check
import sys
from decimal import Decimal

if sys.version_info[0] != 3:
  try:
    print("This script requires Python 3")
  except SyntaxError as err:
    raise err


pi = Decimal("3.1415926535897932384626433832795028841971693993751058209749445923078164062862089986280348253421170679821480865132823066470938446095505822317253594081284811174502841027019385211055596446229489549303819644288109756659334461284756482337867831652712019091456485669234603486104543266482133936072602491412737245870066063155881748815209209628292540917153643678925903600113305305488204665213841469519415116094330572703657595919530921861173819326117931051185480744623799627495673518857527248912279381830119491298336733624406566430860213949463952247371907021798609437027705392171762931767523846748184676694051320005681271452635608277857713427577896091736371787214684409012249534301465495853710507922796892589235420199561121290219608640344181598136297747713099605187072113499999983729780499510597317328160963185950244594553469083026425223082533446850352619311881710100031378387528865875332083814206171776691473035982534904287554687311595628638823537875937519577818577805321712268066130019278766111959092164201989")


def set_prec():
    try:
        context = decimal.Context(
            prec=int(input("precesion(no.of digits required):- "))
            )
        decimal.setcontext(context)
    except ValueError:
        try:
            print("enter a natural no.!")
            context = decimal.Context(
                prec=int(input("precesion(no.of digits required):- "))
                )
            decimal.setcontext(context)
        except ValueError:
            print("precision has been set to 500")
            context = decimal.Context(prec=500)
            decimal.setcontext(context)
        except OverflowError:
            print("precision has been set to 500")
            context = decimal.Context(prec=500)
            decimal.setcontext(context)
    except OverflowError:
        try:
            print("integer too large")
            context = decimal.Context(
                prec=int(input("precesion(no.of digits required):- "))
                )
            decimal.setcontext(context)
        except ValueError:
            print("not a natural no. - precision has been set to 500")
            context = decimal.Context(prec=500)
            decimal.setcontext(context)
        except OverflowError:
            print("integer too big - precision has been set to 500")
            context = decimal.Context(prec=500)
            decimal.setcontext(context)


class op:
    @staticmethod
    def add():
        """a function that prompts the user to add complex no.s"""
        set_prec()
        try:
            x = Decimal(input("value 1: "))
            y = Decimal(input("value 2: "))
            ans = x + y
            print(Decimal(ans))
        except ValueError:
            print("invalid character in input")
            x = Decimal(input("value 1: "))
            y = Decimal(input("value 2: "))
            ans = x + y
            print(Decimal(ans))

    @staticmethod
    def sub():
        set_prec()
        try:
            x = Decimal(input("value 1: "))
            y = Decimal(input("value 2: "))
            ans = x - y
            print(Decimal(ans))
        except ValueError:
            print("invalid character in input")
            x = Decimal(input("value 1: "))
            y = Decimal(input("value 2: "))
            ans = x - y
            print(Decimal(ans))

    @staticmethod
    def multi():
        set_prec()
        try:
            x = Decimal(input("value 1: "))
            y = Decimal(input("value 2: "))
            ans = x * y
            print(Decimal(ans))
        except ValueError:
            print("invalid character in input")

    @staticmethod
    def div():
        try:
            set_prec()
            x = Decimal(input("value 1: "))
            y = Decimal(input("value 2: "))
            ans = x / y
            print(Decimal(ans))
        except ValueError:
            print("invalid character in input")
        except ZeroDivisionError:
            print("Can't divide by Zero")


class con():
    @staticmethod
    def c2j():
        set_prec()
        try:
            x = Decimal(input("calories: "))
            ans = Decimal(x * 4.18400)
            print(ans)
        except ValueError:
            print("invalid character in input")

    @staticmethod
    def j2c():
        set_prec()
        try:
            c = Decimal('4.18400')
            x = Decimal(input("joules: "))
            ans = Decimal(x / c)
            print(ans)
        except ValueError:
            print("invalid character in input")
            c = Decimal('4.18400')
            x = Decimal(input("joules: "))
            ans = Decimal(x / c)
            print(ans)


class vol():
    @staticmethod
    def cube():
        set_prec()
        try:
            x = Decimal(input("side / val: "))
            print(x * x * x + " units")
        except ValueError:
            print("invalid character in input")
            x = Decimal(input("side / val: "))
            print(x * x * x + " units")

    @staticmethod
    def cuboid():
        set_prec()
        try:
            l = Decimal(input("lenght: "))
            h = Decimal(input("height: "))
            b = Decimal(input("breadth: "))
            ans = l * b * h
            print(Decimal(ans))
        except ValueError:
            print("invalid character in input")
            l = Decimal(input("lenght: "))
            h = Decimal(input("height: "))
            b = Decimal(input("breadth: "))
            ans = l * b * h
            print(Decimal(ans))

    @staticmethod
    def cyl():
        set_prec()
        try:
            r = Decimal(input("radius: "))
            h = Decimal(input("height: "))
            ans = pi * r * r * h
            print(Decimal(ans))
        except ValueError:
            print("invalid character in input")
            r = Decimal(input("radius: "))
            h = Decimal(input("height: "))
            ans = pi * r * r * h
            print(Decimal(ans))


class ar():
    @staticmethod
    def rect():
        set_prec()
        try:
            l = Decimal(input("lenght: "))
            b = Decimal(input("breadth: "))
            ans = l * b
            print(Decimal(ans))
        except ValueError:
            print("invalid character in input")
        return l * b

    @staticmethod
    def sq():
        set_prec()
        try:
            s = Decimal(input("side: "))
            ans = s * s * 2
            print(Decimal(ans))
        except ValueError:
            print("invalid character in input")

    @staticmethod
    def circle():
        set_prec()
        try:
            r = Decimal(input("radius: "))
            ans = pi * r * r
            print(Decimal(ans))
        except ValueError:
            print("invalid character in input")


class sa():
    @staticmethod
    def cube():
        set_prec()
        # surface area of cube
        try:
            s = Decimal(input("side: "))
            ans = s * s * 6
            print(Decimal(ans))
        except ValueError:
            print("invalid character in input")

    @staticmethod
    def cyl():
        # t.s.a
        set_prec()
        try:
            r = Decimal(input("radius: "))
            h = Decimal(input("height: "))
            ans = 2 * pi * r * (r + h)
            print(Decimal(ans))
        except ValueError:
            print("invalid character in input")

    @staticmethod
    def cuboid():
        set_prec()
        try:
            l = Decimal(input("lenght: "))
            h = Decimal(input("height: "))
            b = Decimal(input("breadth: "))
            ans = 2 * (l * b) + 2 * (l * h) + 2 * (b * h)
            print(Decimal(ans))
        except ValueError:
            print("invalid character in input")


class lsa():
    @staticmethod
    def cyl():
        set_prec()
        try:
            r = Decimal(input("radius: "))
            h = Decimal(input("height: "))
            ans = 2 * pi * r * h
            print(Decimal(ans))
        except ValueError:
            print("invalid character in input")

    @staticmethod
    def cube():
        set_prec()
        try:
            s = Decimal(input("side: "))
            ans = Decimal(s * s) * 4
            print(Decimal(ans))
        except ValueError:
            print("invalid character in input")

    @staticmethod
    def cuboid():
        set_prec()
        try:
            l = Decimal(input("lenght: "))
            h = Decimal(input("height: "))
            b = Decimal(input("breadth: "))
            ans = 2 * (l * b) + 2 * (l * h)
            print(Decimal(ans))
        except ValueError:
            print("invalid character in input")

#interactive class end
# class end

class Pop:
    @staticmethod
    def add(x, y):
        return x + y

    @staticmethod
    def sub(x, y):
        return x - y

    @staticmethod
    def multi(x, y):
        return x * y

    @staticmethod
    def div(x, y):
        return x / y


class Pcon():
    @staticmethod
    def c2j(x):
        return x * 4.18400

    @staticmethod
    def j2c(x):
        return x / 4.18400


class Pvol():
    @staticmethod
    def cube(x):
        return x ** 3

    @staticmethod
    def cuboid(l, b, h):
        ans = l * b * h
        return ans

    @staticmethod
    def cyl(r, h):
        ans = pi * r * r * h
        return ans


class Par():
    @staticmethod
    def rect(l, b):
        ans = l * b
        return ans

    @staticmethod
    def sq(s):
        ans = s ** 2
        return ans


class Psa():
    @staticmethod
    def cube(s):
        # surface area of cube
        ans = s * s * 6
        return ans

    @staticmethod
    def cylinder(r, h):
        # t.s.a
        ans = 2 * pi * r * (r + h)
        return ans


class Plsa():
    @staticmethod
    def cyl(r, h):
        ans = 2 * pi * r * h
        return ans

    @staticmethod
    def cube(s):
        ans = Decimal(s ** 2) * 4
        return ans

    @staticmethod
    def cuboid(l, b, h):
        ans = 2 * (l * b) + 2 * (l * h)
        return ans

# class end
#---------------------------------------------------- END OF FILE ----------------------------------------------------#