Write a code to input a binary number and convert it to a decimal number.

For example:

ex.1 - 1111 in decimal is

1*(2^3) +1*(2^2) +1*(2^1) +1*(2^0)

= 8 + 4 + 2 + 1

= 15 in decimal.

ex.2 - 10101 in decimal is

1*(2^4) +0*(2^3) +1*(2^2) +0*(2^1) +1*(2^0)

= 16 + 0 + 4 + 0 + 1

= 21 in decimal.

The number of digits to be entered by the user in the binary number has no fixed size input (user can enter any number of bits).

Sample Output:

Enter the binary number

1 1 0 1

The decimal number is: 13