C++ code:

Ask the user for a binary number (1s and 0s).

If they type something other than 1s and 0s, give an error message

Convert the binary number to decimal and display it.

NO C++ built in libraries, functions or keywords.

You must do this with your own independently developed code.

Note: Cap the length of the binary number to 8 bits. If they type more than that, give them an error message.