Calculator¶

This is a very easy calculator by writing a class

import math

class Calculator:
    """A Calculator which has a list of results and the option to add, substract, divide, multiply, pow and squareroot"""
    results = []

    # init method
    def __init__(self):
        self.results = []
    
    
    def add(self,a,b):
        """a and b must be numbers, the numbers will be added and returned. The result will be stored in the results history"""
        self.results.append("%f + %f" % (a,b))
        self.results.append(a+b)
        return a+b
    
    def substract(self,a,b):
        """a and b must be numbers, the numbers will be substaced and returned. The result will be stored in the results history"""
        self.results.append("%f - %f" % (a,b))
        self.results.append(a-b)
        return a-b
    
    def multiply(self,a,b):
        """a and b must be numbers, the numbers will be multiplied and returned. The result will be stored in the results history"""
        self.results.append("%f * %f" % (a,b))
        self.results.append(a*b)
        return a*b
    
    def divide(self,a,b):
        """a and b must be numbers, the numbers will be divided and returned. The result will be stored in the results history"""
        self.results.append("%f / %f" % (a,b))
        try: 
            temp_result = a/b
        except ZeroDivisionError:
            self.results.append("division by zero is not allowed")
            return('division by zero is not allowed')
        else:
            self.results.append("the division is not possible")
            return "the division is not possible"   
        self.results.append(temp_result)
        return temp_result
    
    def pow(self,a,b):
        """a and b must be numbers, a pow b will be calculated and returned. The result will be stored in the results history"""
        self.results.append("%f ** %f" % (a,b))
        self.results.append(pow(a,b))
        return pow(a,b)
    
    def sqrt(self,a):
        """a must be a number, squareroot of a will be calculated and returned. The result will be stored in the results history"""
        self.results.append("sqrt(%f)" % (a))
        self.results.append(math.sqrt(a))
        return math.sqrt(a)   
    
    def print_history(self):
        for i in self.results:
            print(i)

calc = Calculator()

calc.add(3,4)

calc.add(2,4)

calc.divide(2,0)

'division by zero is not allowed'

calc.divide(4,2)

2.0

calc.multiply(3,4)

calc.substract(4,5)

-1

calc.pow(2,2)

calc.sqrt(4)

2.0

calc.print_history()

3.000000 + 4.000000
7
2.000000 + 4.000000
6
2.000000 / 0.000000
the division is not possible
4.000000 / 2.000000
2.0
3.000000 * 4.000000
12
4.000000 - 5.000000
-1
2.000000 ** 2.000000
4
sqrt(4.000000)
2.0

calc2 = Calculator()

calc2.add(3,3)

calc2.print_history()

3.000000 + 3.000000
6

calc2.add(2.3,4.1)

6.3999999999999995

calc.print_history()

3.000000 + 4.000000
7
2.000000 + 4.000000
6
2.000000 / 0.000000
the division is not possible
4.000000 / 2.000000
2.0
3.000000 * 4.000000
12
4.000000 - 5.000000
-1
2.000000 ** 2.000000
4
sqrt(4.000000)
2.0