hamming_code.py

def calculate_parity_bits(data):
    """Generates a dynamic Hamming Code codeword."""
    n = len(data)
    r = 0
    
    # 1. Figure out how many redundant (parity) bits we need
    while (2 ** r) < (n + r + 1):
        r += 1

    # 2. Build the initial codeword array
    # Put 0s in the parity positions (powers of 2) and fill the rest with data bits
    codeword = []
    data_index = 0
    
    for position in range(1, n + r + 1):
        # A bitwise trick: if (position & (position - 1)) == 0, it's a power of 2
        if (position & (position - 1)) == 0:  
            codeword.append(0)
        else:
            codeword.append(int(data[data_index]))
            data_index += 1

    # 3. Calculate the actual values for the Parity Bits
    for i in range(r):
        parity_pos = 2 ** i
        current_parity_value = 0
        
        # Check every bit in the codeword to see if this parity bit is responsible for it
        for target_pos in range(1, len(codeword) + 1):
            # Bitwise AND checks if the target position is covered by the parity position
            if target_pos & parity_pos:
                current_parity_value ^= codeword[target_pos - 1]
                
        # Insert the calculated parity value back into the codeword
        codeword[parity_pos - 1] = current_parity_value

    # Convert the list of integers back into a single string
    return "".join(map(str, codeword))

if __name__ == "__main__":
    data_bits = input("Enter data bits (binary): ").strip()
    result = calculate_parity_bits(data_bits)
    print(f"Hamming Code: {result}")