Swap two variables without using the third variable

Swap two variables without using the third variable in Python

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In this tutorial you will learn how to Swap two numbers without using third variable in Python programming language.

This swapping of two numbers in python program is very frequently asked question in interview and also it is very important program.

Before directly moving on writing the program lets understand what is our aim to achieve in this program.

Basically Swapping of number means 

Suppose variable a has assigned value is 2 and the variable b has assigned value 4 then in swapping operation we will exchange the value and assign value of a i.e 2 in b and the value of b i.e. 4 in variable a.

How our program will behave?

As we already seen above that what we have to achieve in the program.

In the swapping program without using third variable we will assign two different value to the different variables.

For example: a=2 and b=4

Now after execution of the program our output should like 

a=4 and b = 2

Python program to swap two number without using third variable

a = int(input("please give first number a: "))
b = int(input("please give second number b: "))
a=a-b
b=a+b
a=b-a
print("After swapping")
print("value of a is : ", a);
print("value of b is : ", b);

Output:

please give first number a: 6
please give second number b: 3
After swapping
value of a is :  3
value of b is :  6

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