559 lines
22 KiB
Markdown
559 lines
22 KiB
Markdown
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---
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title: Strings
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TARGET DECK: Obsidian::STEM
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FILE TAGS: c17
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tags:
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- c17
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---
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## Overview
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A contiguous sequence of characters terminated by the `NUL` character (refer to [[ascii|ASCII]]). Text data is said to be more platform-independent than [[endianness|binary]] data since it is unaffected by word size or byte ordering.
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%%ANKI
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Basic
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What is a C-style string?
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Back: A character array terminated with a `NUL` character.
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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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<!--ID: 1707758281264-->
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END%%
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%%ANKI
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Basic
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What character terminates all C-style strings?
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Back: `NUL`
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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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<!--ID: 1707758281266-->
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END%%
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%%ANKI
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Basic
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What is the decimal value of `NUL` in ASCII encoding?
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Back: `0`
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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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<!--ID: 1707758281268-->
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END%%
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%%ANKI
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Basic
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Text is more platform-independent than binary because it is unaffected by what two properties?
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Back: Word size and byte ordering.
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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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<!--ID: 1707758281270-->
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END%%
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## `printf`
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The syntax for the format placeholder is `%[flags][width][.precision][length]specifier`.
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%%ANKI
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Basic
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Which header file contains `printf` functionality?
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Back: `stdio.h`
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Reference: “Printf,” in *Wikipedia*, January 18, 2024, [https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962](https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962).
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<!--ID: 1708384441467-->
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END%%
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%%ANKI
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Cloze
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{1:`width`} field specifies a {2:minimum} number of characters while {2:`precision`} specifies a {1:maximum}.
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Reference: “Printf,” in *Wikipedia*, January 18, 2024, [https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962](https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962).
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<!--ID: 1708384441472-->
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END%%
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%%ANKI
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Cloze
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The {`width` and `precision`} fields are output related whereas the {`length`} field is input related.
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Reference: “Printf,” in *Wikipedia*, January 18, 2024, [https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962](https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962).
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<!--ID: 1708425941269-->
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END%%
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Flag | Description
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--------- | -----------
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`-` | Left-aligns the output
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`+` | Prepends a plus for positive signed-numeric types
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`␣` | Prepends a space for positive signed-numeric types
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`0` | Prepends zeros for numeric types
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%%ANKI
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Cloze
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The {`-`} flag {left-aligns the output}.
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Reference: “Printf,” in *Wikipedia*, January 18, 2024, [https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962](https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962).
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<!--ID: 1707918756812-->
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END%%
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%%ANKI
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Basic
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What is the output of `printf("%-2d abc", 100)`?
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Back: `100 abc`
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Reference: “Printf,” in *Wikipedia*, January 18, 2024, [https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962](https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962).
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<!--ID: 1708384441477-->
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END%%
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%%ANKI
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Basic
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What is the output of `printf("%-4d abc", 100)`?
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Back: `100 abc`
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Reference: “Printf,” in *Wikipedia*, January 18, 2024, [https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962](https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962).
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<!--ID: 1708384441481-->
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END%%
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%%ANKI
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Basic
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What is the output of `printf("%.4d abc", 100)`?
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Back: `0100 abc`
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Reference: “Printf,” in *Wikipedia*, January 18, 2024, [https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962](https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962).
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<!--ID: 1708384441486-->
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END%%
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%%ANKI
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Basic
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What is the output of `printf("%04d abc", 100)`?
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Back: `0100 abc`
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Reference: “Printf,” in *Wikipedia*, January 18, 2024, [https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962](https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962).
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<!--ID: 1708384441491-->
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END%%
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%%ANKI
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Basic
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What is the output of `printf("%.4s abc", "efg")`?
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Back: `efg abc`
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Reference: “Printf,” in *Wikipedia*, January 18, 2024, [https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962](https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962).
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<!--ID: 1708384441495-->
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END%%
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%%ANKI
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Basic
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What is the output of `printf("%.2s abc", "efg")`?
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Back: `ef abc`
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Reference: “Printf,” in *Wikipedia*, January 18, 2024, [https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962](https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962).
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<!--ID: 1708384441499-->
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END%%
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%%ANKI
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Basic
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What is the output of `printf("%.2f abc", 0.01234)`?
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Back: `0.01 abc`
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Reference: “Printf,” in *Wikipedia*, January 18, 2024, [https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962](https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962).
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<!--ID: 1708384441503-->
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END%%
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%%ANKI
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Basic
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How does the precision field affect `"%s"` parameters?
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Back: Strings are truncated if longer than the specified precision.
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Reference: “Printf,” in *Wikipedia*, January 18, 2024, [https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962](https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962).
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<!--ID: 1708384441507-->
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END%%
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%%ANKI
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Basic
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How does the precision field affect `"%f"` parameters?
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Back: Decimal values are truncated if longer than the specified precision.
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Reference: “Printf,” in *Wikipedia*, January 18, 2024, [https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962](https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962).
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<!--ID: 1708384441511-->
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END%%
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%%ANKI
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Basic
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What does a negative width field value indicate?
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Back: This is actually a positive width with a `-` (left-align) flag.
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Reference: “Printf,” in *Wikipedia*, January 18, 2024, [https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962](https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962).
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<!--ID: 1708384441515-->
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END%%
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%%ANKI
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Basic
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The `-` `printf` flag overrides what default behavior?
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Back: Output is right-aligned by default.
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Reference: “Printf,” in *Wikipedia*, January 18, 2024, [https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962](https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962).
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<!--ID: 1707918756840-->
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END%%
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%%ANKI
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Cloze
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The {`+`} `printf` flag {prepends a plus for positive signed-numeric types}.
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Reference: “Printf,” in *Wikipedia*, January 18, 2024, [https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962](https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962).
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<!--ID: 1707918756846-->
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END%%
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%%ANKI
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Basic
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The `+` `printf` flag overrides what default behavior?
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Back: Nothing is prepended to positive signed-numeric types by default.
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Reference: “Printf,” in *Wikipedia*, January 18, 2024, [https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962](https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962).
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<!--ID: 1707918756852-->
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END%%
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%%ANKI
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Cloze
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The {`␣`} `printf` flag {prepends a space for positive signed-numeric types}.
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Reference: “Printf,” in *Wikipedia*, January 18, 2024, [https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962](https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962).
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<!--ID: 1707918756856-->
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END%%
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%%ANKI
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Basic
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The `␣` `printf` flag overrides what default behavior?
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Back: Nothing is prepended to positive signed-numeric types by default.
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Reference: “Printf,” in *Wikipedia*, January 18, 2024, [https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962](https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962).
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<!--ID: 1707918756861-->
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END%%
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%%ANKI
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Basic
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How do the `+` and `␣` `printf` flags relate to one another?
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Back: Both prepend a character to positive signed-numeric types.
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Reference: “Printf,” in *Wikipedia*, January 18, 2024, [https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962](https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962).
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<!--ID: 1707918756865-->
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END%%
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%%ANKI
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Basic
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What happens if both the `+` and `␣` `printf` flags are specified?
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Back: The `+` flag takes precedence.
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Reference: “Printf,” in *Wikipedia*, January 18, 2024, [https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962](https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962).
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<!--ID: 1707918756870-->
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END%%
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%%ANKI
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Cloze
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The {`0`} `printf` flag {prepends zeros for numeric types}.
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Reference: “Printf,” in *Wikipedia*, January 18, 2024, [https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962](https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962).
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<!--ID: 1707918756875-->
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END%%
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%%ANKI
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Basic
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What option must be specified for the `0` `printf` flag to take effect?
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Back: The "width" option.
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Reference: “Printf,” in *Wikipedia*, January 18, 2024, [https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962](https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962).
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<!--ID: 1707918756881-->
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END%%
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%%ANKI
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Basic
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The `0` `printf` flag overrides what default behavior?
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Back: Spaces are used to match the "width" option by default.
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Reference: “Printf,” in *Wikipedia*, January 18, 2024, [https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962](https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962).
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<!--ID: 1707918756888-->
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END%%
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Length | Description
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--------- | -----------
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`hh` | `int` sized integer argument promoted from a `char`
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`h` | `int` sized integer argument promoted from a `short`
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`l` | `long` sized integer argument
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`ll` | `long long` sized integer argument
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`z` | `size_t` sized integer argument
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%%ANKI
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Basic
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*Why* do length modifiers for e.g. `char` exist?
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Back: For maximum portability in the face of default argument promotions.
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Reference: “Printf,” in *Wikipedia*, January 18, 2024, [https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962](https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962).
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<!--ID: 1708426673637-->
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END%%
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%%ANKI
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Cloze
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The {`hh`} length corresponds to the {`char`} type declaration.
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Reference: “Printf,” in *Wikipedia*, January 18, 2024, [https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962](https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962).
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<!--ID: 1708426673664-->
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END%%
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%%ANKI
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Cloze
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The {`h`} length corresponds to the {`short`} type declaration.
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Reference: “Printf,” in *Wikipedia*, January 18, 2024, [https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962](https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962).
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<!--ID: 1708426673668-->
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END%%
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%%ANKI
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Cloze
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The {`l`} length corresponds to the {`long`} type declaration.
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Reference: “Printf,” in *Wikipedia*, January 18, 2024, [https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962](https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962).
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<!--ID: 1708426673711-->
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END%%
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%%ANKI
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Cloze
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The {`ll`} length corresponds to the {`long long`} type declaration.
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Reference: “Printf,” in *Wikipedia*, January 18, 2024, [https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962](https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962).
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<!--ID: 1708426673719-->
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END%%
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%%ANKI
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Cloze
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The {`z`} length corresponds to the {`size_t`} type declaration.
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Reference: “Printf,” in *Wikipedia*, January 18, 2024, [https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962](https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962).
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<!--ID: 1708426673725-->
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END%%
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Specifier | Description
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--------- | -----------
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`d`, `i` | a decimal `signed int`
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`u` | a decimal `unsigned int`
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`x` | a hexadecimal `unsigned int` (lowercase)
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`X` | a hexadecimal `unsigned int` (uppercase)
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`o` | an octal `unsigned int`
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`s` | a `NUL`-terminated string
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`c` | a `char` character
|
||
|
|
`p` | `void*` address in an implementation-defined format
|
||
|
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|
||
|
|
%%ANKI
|
||
|
|
Basic
|
||
|
|
What character do `printf` format specifiers start with?
|
||
|
|
Back: `%`
|
||
|
|
Reference: “Printf,” in *Wikipedia*, January 18, 2024, [https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962](https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962).
|
||
|
|
Tags: printf
|
||
|
|
<!--ID: 1707852083029-->
|
||
|
|
END%%
|
||
|
|
|
||
|
|
%%ANKI
|
||
|
|
Basic
|
||
|
|
Why is `printf` named the way it is?
|
||
|
|
Back: It stands for **print f**ormatted.
|
||
|
|
Reference: “Printf,” in *Wikipedia*, January 18, 2024, [https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962](https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962).
|
||
|
|
Tags: printf
|
||
|
|
<!--ID: 1707852083037-->
|
||
|
|
END%%
|
||
|
|
|
||
|
|
%%ANKI
|
||
|
|
Cloze
|
||
|
|
The {`%d` and `%i`} format specifers work on a {decimal `signed int`}.
|
||
|
|
Reference: “Printf,” in *Wikipedia*, January 18, 2024, [https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962](https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962).
|
||
|
|
Tags: printf
|
||
|
|
<!--ID: 1707852083040-->
|
||
|
|
END%%
|
||
|
|
|
||
|
|
%%ANKI
|
||
|
|
Cloze
|
||
|
|
{`%d` and `%i`} are to `signed` as {`%u`} is to `unsigned`.
|
||
|
|
Reference: “Printf,” in *Wikipedia*, January 18, 2024, [https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962](https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962).
|
||
|
|
Tags: printf
|
||
|
|
<!--ID: 1707852083044-->
|
||
|
|
END%%
|
||
|
|
|
||
|
|
%%ANKI
|
||
|
|
Cloze
|
||
|
|
The {`%u`} format specifier outputs a {decimal `unsigned int`}.
|
||
|
|
Reference: “Printf,” in *Wikipedia*, January 18, 2024, [https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962](https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962).
|
||
|
|
Tags: printf
|
||
|
|
<!--ID: 1707852083047-->
|
||
|
|
END%%
|
||
|
|
|
||
|
|
%%ANKI
|
||
|
|
Basic
|
||
|
|
What distinguishes format specifiers `%d` and `%i`?
|
||
|
|
Back: Nothing.
|
||
|
|
Reference: “Printf,” in *Wikipedia*, January 18, 2024, [https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962](https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962).
|
||
|
|
Tags: printf
|
||
|
|
<!--ID: 1707852083050-->
|
||
|
|
END%%
|
||
|
|
|
||
|
|
%%ANKI
|
||
|
|
Basic
|
||
|
|
Which format specifiers were probably used to yield `printf` output `-12`?
|
||
|
|
Back: `%d` or `%i`
|
||
|
|
Reference: “Printf,” in *Wikipedia*, January 18, 2024, [https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962](https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962).
|
||
|
|
Tags: printf
|
||
|
|
<!--ID: 1707852083054-->
|
||
|
|
END%%
|
||
|
|
|
||
|
|
%%ANKI
|
||
|
|
Basic
|
||
|
|
What distinguishes format specifiers `%d` and `%u`?
|
||
|
|
Back: The former is for signed integers, the latter unsigned.
|
||
|
|
Reference: “Printf,” in *Wikipedia*, January 18, 2024, [https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962](https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962).
|
||
|
|
Tags: printf
|
||
|
|
<!--ID: 1707852083058-->
|
||
|
|
END%%
|
||
|
|
|
||
|
|
%%ANKI
|
||
|
|
Cloze
|
||
|
|
The {`%x`} format specifier outputs a {lowercase hexadecimal `unsigned int`}.
|
||
|
|
Reference: “Printf,” in *Wikipedia*, January 18, 2024, [https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962](https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962).
|
||
|
|
Tags: printf
|
||
|
|
<!--ID: 1707852083063-->
|
||
|
|
END%%
|
||
|
|
|
||
|
|
%%ANKI
|
||
|
|
Basic
|
||
|
|
Which format specifier were probably used to yield `printf` output `7af`?
|
||
|
|
Back: `%x`
|
||
|
|
Reference: “Printf,” in *Wikipedia*, January 18, 2024, [https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962](https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962).
|
||
|
|
Tags: printf
|
||
|
|
<!--ID: 1707852083068-->
|
||
|
|
END%%
|
||
|
|
|
||
|
|
%%ANKI
|
||
|
|
Cloze
|
||
|
|
The {`%X`} format specifier outputs an {uppercase hexadecimal `unsigned int`}.
|
||
|
|
Reference: “Printf,” in *Wikipedia*, January 18, 2024, [https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962](https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962).
|
||
|
|
Tags: printf
|
||
|
|
<!--ID: 1707852083074-->
|
||
|
|
END%%
|
||
|
|
|
||
|
|
%%ANKI
|
||
|
|
Basic
|
||
|
|
Which format specifier were probably used to yield `printf` output `7AF`?
|
||
|
|
Back: `%X`
|
||
|
|
Reference: “Printf,” in *Wikipedia*, January 18, 2024, [https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962](https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962).
|
||
|
|
Tags: printf
|
||
|
|
<!--ID: 1707852083080-->
|
||
|
|
END%%
|
||
|
|
|
||
|
|
%%ANKI
|
||
|
|
Basic
|
||
|
|
What distinguishes format specifiers `%x` and `%X`?
|
||
|
|
Back: The former outputs lowercase hex digits, the latter uppercase.
|
||
|
|
Reference: “Printf,” in *Wikipedia*, January 18, 2024, [https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962](https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962).
|
||
|
|
Tags: printf
|
||
|
|
<!--ID: 1707852083086-->
|
||
|
|
END%%
|
||
|
|
|
||
|
|
%%ANKI
|
||
|
|
Cloze
|
||
|
|
The {`%o`} format specifier outputs an {octal `unsigned int`}.
|
||
|
|
Reference: “Printf,” in *Wikipedia*, January 18, 2024, [https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962](https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962).
|
||
|
|
Tags: printf
|
||
|
|
<!--ID: 1707852083091-->
|
||
|
|
END%%
|
||
|
|
|
||
|
|
%%ANKI
|
||
|
|
Basic
|
||
|
|
Why doesn't the `%o` format specifier have a corresponding `%O` specifier?
|
||
|
|
Back: There is no distinction between lower and uppercase octal digits.
|
||
|
|
Reference: “Printf,” in *Wikipedia*, January 18, 2024, [https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962](https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962).
|
||
|
|
Tags: printf
|
||
|
|
<!--ID: 1707852083096-->
|
||
|
|
END%%
|
||
|
|
|
||
|
|
%%ANKI
|
||
|
|
Cloze
|
||
|
|
The {`%s`} format specifiers outputs a {`NUL`-terminated string}.
|
||
|
|
Reference: “Printf,” in *Wikipedia*, January 18, 2024, [https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962](https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962).
|
||
|
|
Tags: printf
|
||
|
|
<!--ID: 1707852083100-->
|
||
|
|
END%%
|
||
|
|
|
||
|
|
%%ANKI
|
||
|
|
Basic
|
||
|
|
Which format specifier was probably used to yield `printf` output `abc`?
|
||
|
|
Back: `%s`
|
||
|
|
Reference: “Printf,” in *Wikipedia*, January 18, 2024, [https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962](https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962).
|
||
|
|
Tags: printf
|
||
|
|
<!--ID: 1707852083105-->
|
||
|
|
END%%
|
||
|
|
|
||
|
|
%%ANKI
|
||
|
|
Cloze
|
||
|
|
The {`%c`} format specifier outputs a {`char` character}.
|
||
|
|
Reference: “Printf,” in *Wikipedia*, January 18, 2024, [https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962](https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962).
|
||
|
|
Tags: printf
|
||
|
|
<!--ID: 1707852083109-->
|
||
|
|
END%%
|
||
|
|
|
||
|
|
%%ANKI
|
||
|
|
Basic
|
||
|
|
Which format specifier was probably used to yield `printf` output `a`?
|
||
|
|
Back: `%c`
|
||
|
|
Reference: “Printf,” in *Wikipedia*, January 18, 2024, [https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962](https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962).
|
||
|
|
Tags: printf
|
||
|
|
<!--ID: 1707852083113-->
|
||
|
|
END%%
|
||
|
|
|
||
|
|
%%ANKI
|
||
|
|
Cloze
|
||
|
|
The {`%p`} format specifier outputs a {`void*` address}.
|
||
|
|
Reference: “Printf,” in *Wikipedia*, January 18, 2024, [https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962](https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962).
|
||
|
|
Tags: printf
|
||
|
|
<!--ID: 1707852083117-->
|
||
|
|
END%%
|
||
|
|
|
||
|
|
%%ANKI
|
||
|
|
Basic
|
||
|
|
Which format specifier was probably used to yield `printf` output `0b80000000`?
|
||
|
|
Back: `%p`
|
||
|
|
Reference: “Printf,” in *Wikipedia*, January 18, 2024, [https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962](https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962).
|
||
|
|
Tags: printf
|
||
|
|
<!--ID: 1707852083121-->
|
||
|
|
END%%
|
||
|
|
|
||
|
|
%%ANKI
|
||
|
|
Basic
|
||
|
|
How is the address outputted by the `%p` format specifier written?
|
||
|
|
Back: In an implementation-specific way.
|
||
|
|
Reference: “Printf,” in *Wikipedia*, January 18, 2024, [https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962](https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962).
|
||
|
|
Tags: printf
|
||
|
|
<!--ID: 1707852083126-->
|
||
|
|
END%%
|
||
|
|
|
||
|
|
%%ANKI
|
||
|
|
Basic
|
||
|
|
Given `int64_t x`, why is `printf("%d", x)` a problem?
|
||
|
|
Back: `%d` matches an `int` which is not necessarily 64-bits.
|
||
|
|
Tags: printf
|
||
|
|
Reference: Bryant, Randal E., and David O'Hallaron. *Computer Systems: A Programmer's Perspective*. Third edition, Global edition. Always Learning. Pearson, 2016.
|
||
|
|
<!--ID: 1708454462772-->
|
||
|
|
END%%
|
||
|
|
|
||
|
|
%%ANKI
|
||
|
|
Basic
|
||
|
|
What must you use when invoking `printf` with a fixed-width integer type?
|
||
|
|
Back: `printf`-specific macros.
|
||
|
|
Reference: Bryant, Randal E., and David O'Hallaron. *Computer Systems: A Programmer's Perspective*. Third edition, Global edition. Always Learning. Pearson, 2016.
|
||
|
|
Tags: printf
|
||
|
|
<!--ID: 1708454462777-->
|
||
|
|
END%%
|
||
|
|
|
||
|
|
%%ANKI
|
||
|
|
Basic
|
||
|
|
What is `PRId32` an example macro for?
|
||
|
|
Back: A macro that expands to the correct specifier for a 32-bit signed integral type.
|
||
|
|
Reference: Bryant, Randal E., and David O'Hallaron. *Computer Systems: A Programmer's Perspective*. Third edition, Global edition. Always Learning. Pearson, 2016.
|
||
|
|
Tags: printf
|
||
|
|
<!--ID: 1708454462780-->
|
||
|
|
END%%
|
||
|
|
|
||
|
|
%%ANKI
|
||
|
|
Cloze
|
||
|
|
{`PRId32`} is to signed whereas {`PRIu32`} is to unsigned.
|
||
|
|
Reference: “Printf,” in *Wikipedia*, January 18, 2024, [https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962](https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962).
|
||
|
|
Tags: printf
|
||
|
|
<!--ID: 1708454462784-->
|
||
|
|
END%%
|
||
|
|
|
||
|
|
%%ANKI
|
||
|
|
Basic
|
||
|
|
Which C header specifies `printf` macros for fixed-width integral types?
|
||
|
|
Back: `<inttypes.h>`
|
||
|
|
Reference: “Printf,” in *Wikipedia*, January 18, 2024, [https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962](https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962).
|
||
|
|
Tags: printf
|
||
|
|
<!--ID: 1708454462788-->
|
||
|
|
END%%
|
||
|
|
|
||
|
|
%%ANKI
|
||
|
|
Basic
|
||
|
|
Given `int32_t x`, how might we invoke `printf` on it?
|
||
|
|
Back: `printf("%" PRId32, x)`
|
||
|
|
Reference: Bryant, Randal E., and David O'Hallaron. *Computer Systems: A Programmer's Perspective*. Third edition, Global edition. Always Learning. Pearson, 2016.
|
||
|
|
Tags: printf
|
||
|
|
<!--ID: 1708454584564-->
|
||
|
|
END%%
|
||
|
|
|
||
|
|
%%ANKI
|
||
|
|
Basic
|
||
|
|
What prefix do `printf` macros from `<inttypes.h>` share?
|
||
|
|
Back: `PRI`
|
||
|
|
Reference: Bryant, Randal E., and David O'Hallaron. *Computer Systems: A Programmer's Perspective*. Third edition, Global edition. Always Learning. Pearson, 2016.
|
||
|
|
Tags: printf
|
||
|
|
<!--ID: 1708454584568-->
|
||
|
|
END%%
|
||
|
|
|
||
|
|
## References
|
||
|
|
|
||
|
|
* Bryant, Randal E., and David O'Hallaron. *Computer Systems: A Programmer's Perspective*. Third edition, Global edition. Always Learning. Pearson, 2016.
|
||
|
|
* “Printf,” in *Wikipedia*, January 18, 2024, [https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962](https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962).
|