Binary File Reading (BMP Example) - Python Programming Exercise

def verify_bmp_header(file_name):
    """
    Verifies if the given file is a valid BMP image by checking its header.
    
    Parameters:
    file_name (str): The name of the file to check.
    
    Returns:
    bool: True if the file is a valid BMP, False otherwise.
    """
    try:
        with open(file_name, 'rb') as file:
            # Read the first two bytes of the file
            header = file.read(2)
            
            # Check if the first two bytes match 'B' and 'M' (0x42 and 0x4D)
            if header == b'BM':
                return True
            else:
                return False
            
    except FileNotFoundError:
        print(f"The file '{file_name}' was not found.")
        return False
    except Exception as e:
        print(f"An error occurred: {e}")
        return False

# Main program execution
if __name__ == "__main__":
    # Ask the user to input the file name
    file_name = input("Please enter the BMP file name to verify: ")
    
    # Verify if the file is a valid BMP image
    if verify_bmp_header(file_name):
        print(f"The file '{file_name}' is a valid BMP image.")
    else:
        print(f"The file '{file_name}' is not a valid BMP image.")

 Output

Assume you have a BMP file named image.bmp. When you run the program, it will behave as follows:

Please enter the BMP file name to verify: image.bmp
The file 'image.bmp' is a valid BMP image.

If the file is not a BMP or the header does not match "BM", the program will output:

Please enter the BMP file name to verify: image.jpg
The file 'image.jpg' is not a valid BMP image.

If the file does not exist, it will output:

Please enter the BMP file name to verify: nonexistent.bmp
The file 'nonexistent.bmp' was not found.