Python Program to find swap two numbers without temp variable (Addition and Subtraction Method)

Program

a = int(input("Enter the value of a:\t"))
b = int(input("Enter the value of b:\t"))
print("Values before swapping:")
print("a:\t{}\nb:\t{}".format(a,b))
a = a + b
b = a - b
a = a - b
print("Values after swapping:")
print("a:\t{}\nb:\t{}".format(a,b))

This program swaps two numbers without using a temporary variable by using addition and subtraction.

a = int(input("Enter the value of a:\t"))
b = int(input("Enter the value of b:\t"))

• The user inputs two numbers (a and b).
• input() takes input as a string, and int() converts it to an integer.

print("Values before swapping:")
print("a:\t{}\nb:\t{}".format(a,b))

• Displays the original values before swapping.

Swapping Logic Using Addition and Subtraction

a = a + b  # Step 1: Store the sum of a and b in a
b = a - b  # Step 2: Subtract b from the new value of a, which gives original a and assigns it to b
a = a - b  # Step 3: Subtract new b (original a) from new a (sum), which gives original b and assigns it to a

• The sum of both numbers is stored in a.
• Then b is updated to a - b, effectively giving b the value of a before swapping.
• Finally, a is updated to a - b, effectively giving a the value of b before swapping.

print("Values after swapping:")
print("a:\t{}\nb:\t{}".format(a,b))

• Prints the swapped values.

Key Takeaways

• Swaps two numbers without using a temporary variable.
• Uses basic arithmetic operations (addition and subtraction).
• Works efficiently for small values but may cause overflow issues for very large numbers in some languages.

Output

Enter the value of a:	12
Enter the value of b:	3
Values before swapping:
a:	12
b:	3
Values after swapping:
a:	3
b:	12