Binary to Decimal Conversion in Python

Binary to Decimal Conversion

Binary to Decimal conversion is the process of converting a binary number (base-2) into its equivalent decimal number (base-10). Each binary digit represents a power of 2.

For example, the binary number 1010 is equal to decimal 10 because:

(1 × 2³) + (0 × 2²) + (1 × 2¹) + (0 × 2⁰) = 8 + 0 + 2 + 0 = 10

We will explore three methods to convert a binary number to a decimal number using Python programming.

Method 1: Using Loop

def binary_to_decimal(binary):
    decimal, i = 0, 0
    while binary:
        last_digit = binary % 10
        decimal += last_digit * (2 ** i)
        binary //= 10
        i += 1
    return decimal
            

Output:

Enter a binary number: 1010
Decimal equivalent (Loop): 10

Method 2: Using Recursion

def binary_to_decimal_recursive(binary, i=0):
    if binary == 0:
        return 0
    return (binary % 10) * (2 ** i) + binary_to_decimal_recursive(binary // 10, i + 1)
            

Output:

Enter a binary number: 1010
Decimal equivalent (Recursion): 10

Method 3: Using Built-in Function

def binary_to_decimal_builtin(binary):
    return int(str(binary), 2)
            

Output:

Enter a binary number: 1010
Decimal equivalent (Built-in): 10

Main Function

binary = int(input("Enter a binary number: "))
print(f"Decimal equivalent (Loop): {binary_to_decimal(binary)}")
print(f"Decimal equivalent (Recursion): {binary_to_decimal_recursive(binary)}")
print(f"Decimal equivalent (Built-in): {binary_to_decimal_builtin(binary)}")