Why can't a variable exceed more than 255 characters?

Answer 1

I think you are talking about characters. The size of char data type is 1 byte which means 8 bits.
So 11111111 -> you add their place values you will get 255.

Answer 2

If any of your veriable is not able to exceed 255 value that means it is stored in 8 bits and rest Avinesh already explained

Answer 3

OK thanks sir 🙏