What is the binary code? ?

It's not "code" as such, just numbers or counting in "base 2", like decimal is base 10.

The digit weights, from right to left, have 2x the value each rather than 10x the value as in decimal.

The lowest four bits (BInary digiTS) have weights of 8, 4, 2, 1.

eg. 101 = 5 decimal.

1000 = 8 decimal

1010 = 10 decimal.

It's quite often shown as groups of four bits, which allows each group to be represented by a number from 0-15 or a "hexadecimal" (base 16) digit.

Values above 9 are represented by letters A - F; the 1010 binary value = "A" in hex.

1100 0110 = C6 in hex; 198 decimal.

(128 + 64 + 4 + 2)

If you switch the Windows calculator view to "Programmer" you can convert to and from binary, hex or octal (groups of three bits) as well as decimal.

You could say that 10110 is a binary code because it consists of just ones and zeroes, or it could just be a decimal number (ten thousand one hundred ten).

Where is your limit?