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| title | TARGET DECK | FILE TAGS | tags | |
|---|---|---|---|---|
| Binary | Obsidian::STEM | binary |
|
Overview
A binary digit or bit is a 0 or 1 character. A bit string is then a contiguous sequence of bits. It's weight is a reference to the number of 1s in the bit string. Compare the below operation to the method for converting from one numerical base to another (e.g. radices#Hexadecimal).
unsigned int bit_weight(int64_t n) {
unsigned int count = 0;
while (n) {
count += (n % 2 == 0) ? 0 : 1;
n /= 2;
}
return count;
}
%%ANKI Basic Why is a "bit" named the way it is? Back: It is short for binary digit. Reference: Oscar Levin, Discrete Mathematics: An Open Introduction, 3rd ed., n.d., https://discrete.openmathbooks.org/pdfs/dmoi3-tablet.pdf.
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Basic
What does the weight of a bit string refer to?
Back: The number of 1s in the string.
Reference: Oscar Levin, Discrete Mathematics: An Open Introduction, 3rd ed., n.d., https://discrete.openmathbooks.org/pdfs/dmoi3-tablet.pdf.
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Basic
How might you use C to find the weight of a bit string?
Back: Repeatedly divide by 2, counting all remainders of 1.
Reference: Oscar Levin, Discrete Mathematics: An Open Introduction, 3rd ed., n.d., https://discrete.openmathbooks.org/pdfs/dmoi3-tablet.pdf.
Tags: c17
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%%ANKI Cloze A byte consists of {8} bits. Reference: Bryant, Randal E., and David O'Hallaron. Computer Systems: A Programmer's Perspective. Third edition, Global edition. Always Learning. Pearson, 2016.
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%%ANKI Cloze A byte consists of {2} nibbles. Reference: Bryant, Randal E., and David O'Hallaron. Computer Systems: A Programmer's Perspective. Third edition, Global edition. Always Learning. Pearson, 2016.
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%%ANKI Cloze A nibble consists of {4} bits. Reference: Bryant, Randal E., and David O'Hallaron. Computer Systems: A Programmer's Perspective. Third edition, Global edition. Always Learning. Pearson, 2016.
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%%ANKI Basic What process is used to convert from e.g. decimal to another base? Back: Divide repeatedly by the base. Maintain remainders right to left. Reference: Bryant, Randal E., and David O'Hallaron. Computer Systems: A Programmer's Perspective. Third edition, Global edition. Always Learning. Pearson, 2016.
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%%ANKI Basic Why does converting from e.g. decimal to another base involve repeated division? Back: The position of a digit corresponds to the base raised to that position. Reference: Bryant, Randal E., and David O'Hallaron. Computer Systems: A Programmer's Perspective. Third edition, Global edition. Always Learning. Pearson, 2016.
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