Prelude to Computer Science - 5: Binary Numbers

Computers use binary numbers internally, because components that use binary are easier and cheaper to build. Whenever you type a number into the computer, it gets converted to binary internally, and then back to decimal for output. (Actually, it's converted to ASCII for output, but that's for a later discussion.)

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• prelude
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[planetlover316]

If I use hexadecimal to represent my 8 digit binary number, can I store that into a cell. Is it 8 bits or just 2 stored in the cell,like "FF"

Also if I move a value to 01 cell from 00 cell. is cell 00 empty. and 01 is overwritten right. Or can it be placed behind another hexadecimal if they can be stored.

[TheFallibleFiend]

I assume a "cell" is a "memory location." An eight 'digit' binary number is 8 bits long and so it requires 8 bits to represent internally. It gets "turned into" the characters "FF" when you attempt to output. In assembler language, you might have to write this conversion yourself. In higher level languages, the formatted print statements do it for you.

The original cell in your example is not "emptied" or zeroed in a copy operation.

[BOGZASV8MA]

great video - thanks for your educational videos.

[TheFallibleFiend]

thanks for watching. good luck in your educational pursuits.

[kikanqa]

how do we represent negative numbers in binary digits???

[TheFallibleFiend]

Example:

say we use3-bit two's complement.

dec binary

0 000

1 001

2 010

-1  111

-2 110

Generally, you can get the negative of a num by reversing bits and adding one. With 3 bits we can represent integers from -4 to positive 3.

[blitz9100]

Thanks, This really helps me a lot!

[youmusicandme]

Your videos are quite helpful and straightforward. Tx man!

[IHACKER316]

excellent thanks a million

[TEXASxDR3W]

Awesome vid thanks

[sloppyjoes]

I'm not sure if you said this, but you did not add what hex is, how binary is easily translated into hex, or what the 0x or 0b prefixes mean if you see them.

Basically if you mentioned binary, hex and dec people would know about every number system the computer uses.

Short of octal, but I've never really seen that used anywhere.

Good video other wise.

[vittorio09]

Thank you!