Operator overloading in python: Python Arithmetic on Complex numbers

Write a sample program to perform Addition(+), Subtraction(-), Multiplication(*),Division(/) between complex numbers. And also perform Mod(underRoot(Square(real)+square(imaginary))) of complex number. 
from math import pow
class complex:
    def __init__(self, real, imag):
        self.real = real
        self.imag = imag
    def __add__(self, other):
        return complex(self.real+other.real, self.imag+other.imag)
    def __sub__(self, other):
        return complex(self.real-other.real, self.imag-other.imag)
    def __mul__(self, other):
        return complex(self.real*other.real-self.imag*other.imag, self.real*other.imag+self.imag*other.real)
    def __div__(self, other):
        try: 
            return self.__mul__(complex(other.real, -1*other.imag)).__mul__(complex(1.0/(other.mod().real)**2, 0))
        except Exception as e:
            print e
            return None
    def mod(self):
        return pow(self.real**2+self.imag**2, 0.5)
    def __str__(self, precision=2):
        return str(("%."+"%df"%precision)%float(self.real))+('+' if self.imag>=0 else '-')+str(("%."+"%df"%precision)%float(abs(self.imag)))+'i'

print "Enter real and imaginary part of complex No - 1(separeated by space)" 
A = complex(*map(float, raw_input().strip().split()))
print "Enter real and imaginary part of complex No - 2(separeated by space)" 
B = complex(*map(float, raw_input().strip().split()))

print "Addition: " + str(A+B)
print "Subtraction: " + str(A-B)
print "Multiplication: " + str(A*B)
print "Division: "+ str(A/B)
print "Modulas of complex Number A: " + str(A.mod())
Sample output:-
>>>
Enter real and imaginary part of complex No - 1
3 4
Enter real and imaginary part of complex No - 2
2 3
Addition: 5.00+7.00i
Subtraction: 1.00+1.00i
Multiplication: -6.00+17.00i
Division: 1.38-0.08i
Modulas of complex Number A: 5.0

Explanation:-
Python provides ability to override inbuilt arithmetic methods like __add__(),__sub__(), etc methods. It is similar to overriding __str__() method to print formatted output(like we have done in above code).For more detail refer this.

What happens internally when we perform + operation between two objects(Remember primitive integer is object in python)?- When we sum two objects in Python, like
a + b
the __add__ method of the a object is called: a.__add__(b)
it means that we can control the result of a sum of two objects by modifying or defining our own __add__ method.


6 Comments

  1. Replies
    1. Operator overloading in Python is a useful object-oriented programming concept that allows arithmetic operators to work with custom objects. This complex-number example clearly demonstrates how methods such as __add__(), __sub__(), and __mul__() can define mathematical operations, while the modulus calculation helps illustrate another important property of complex numbers.

      Working through these examples and experimenting with custom classes can strengthen programming fundamentals, especially for students developing practical applications. Exploring a Python Course in Chennai can help learners build a stronger understanding of Python syntax, object-oriented programming, and advanced language features through structured practice.

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    2. It is also valuable to understand how Python invokes special methods internally when operators are used between objects. A Python Training in Chennai program can provide further opportunities to practice these concepts, improve debugging skills, and apply object-oriented techniques in real-world coding exercises.

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