42 KiB
| title | TARGET DECK | FILE TAGS | tags | |
|---|---|---|---|---|
| Strings | Obsidian::STEM | c17 |
|
Overview
A contiguous sequence of characters terminated by the NUL character (refer to ascii). Text data is said to be more platform-independent than endianness data since it is unaffected by word size or byte ordering.
%%ANKI
Basic
What is a C-style string?
Back: A character array terminated with a NUL character.
Reference: Bryant, Randal E., and David O'Hallaron. Computer Systems: A Programmer's Perspective. Third edition, Global edition. Always Learning. Pearson, 2016.
END%%
%%ANKI
Basic
What character terminates all C-style strings?
Back: NUL
Reference: Bryant, Randal E., and David O'Hallaron. Computer Systems: A Programmer's Perspective. Third edition, Global edition. Always Learning. Pearson, 2016.
END%%
%%ANKI
Basic
What is the decimal value of NUL in ASCII encoding?
Back: 0
Reference: Bryant, Randal E., and David O'Hallaron. Computer Systems: A Programmer's Perspective. Third edition, Global edition. Always Learning. Pearson, 2016.
END%%
%%ANKI Basic Text is more platform-independent than e.g. integer encodings because it is unaffected by what two properties? Back: Word size and byte ordering. Reference: Bryant, Randal E., and David O'Hallaron. Computer Systems: A Programmer's Perspective. Third edition, Global edition. Always Learning. Pearson, 2016.
END%%
printf
The syntax for the format placeholder is %[flags][width][.precision][length]specifier.
%%ANKI
Basic
What four optional parts make up a printf argument?
Back: Flags, width, precision, and length.
Reference: “Printf,” in Wikipedia, January 18, 2024, https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962.
Tags: printf
END%%
%%ANKI
Basic
Which header file contains basic printf functionality?
Back: <stdio.h>
Reference: “Printf,” in Wikipedia, January 18, 2024, https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962.
Tags: printf
END%%
%%ANKI
Cloze
{1:width} specifies a {2:minimum} while {2:precision} specifies a {1:maximum}.
Reference: “Printf,” in Wikipedia, January 18, 2024, https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962.
Tags: printf
END%%
%%ANKI
Cloze
The {width and precision} fields are output related whereas the {length} field is input related.
Reference: “Printf,” in Wikipedia, January 18, 2024, https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962.
Tags: printf
END%%
| Flag | Description |
|---|---|
- |
Left-aligns the output |
+ |
Prepends a plus for positive signed-numeric types |
␣ |
Prepends a space for positive signed-numeric types |
0 |
Prepends zeros for numeric types |
# |
For g and G, trailing zeros are not removed. For f, F, e, E, g, and G, output always has a decimal point. For o, x, and X, the text 0, 0x, and 0X is prepended to nonzero numbers respectively. |
%%ANKI
Cloze
The {-} flag {left-aligns the output}.
Reference: “Printf,” in Wikipedia, January 18, 2024, https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962.
Tags: printf
END%%
%%ANKI
Basic
What is the output of printf("%-2d abc", 100)?
Back: 100␣abc
Reference: “Printf,” in Wikipedia, January 18, 2024, https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962.
Tags: printf
END%%
%%ANKI
Basic
What is the output of printf("%-4d abc", 100)?
Back: 100␣␣abc
Reference: “Printf,” in Wikipedia, January 18, 2024, https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962.
Tags: printf
END%%
%%ANKI
Basic
What is the output of printf("%.4d abc", 100)?
Back: 0100␣abc
Reference: “Printf,” in Wikipedia, January 18, 2024, https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962.
Tags: printf
END%%
%%ANKI
Basic
What is the output of printf("%04d abc", 100)?
Back: 0100␣abc
Reference: “Printf,” in Wikipedia, January 18, 2024, https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962.
Tags: printf
END%%
%%ANKI
Basic
What is the output of printf("%.4s abc", "efg")?
Back: efg␣abc
Reference: “Printf,” in Wikipedia, January 18, 2024, https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962.
Tags: printf
END%%
%%ANKI
Basic
What is the output of printf("%.2s abc", "efg")?
Back: ef␣abc
Reference: “Printf,” in Wikipedia, January 18, 2024, https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962.
Tags: printf
END%%
%%ANKI
Basic
What is the output of printf("%.2f abc", 0.01234)?
Back: 0.01␣abc
Reference: “Printf,” in Wikipedia, January 18, 2024, https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962.
Tags: printf
END%%
%%ANKI
Basic
How does the precision field affect "%s" parameters?
Back: Strings are truncated if longer than the specified precision.
Reference: “Printf,” in Wikipedia, January 18, 2024, https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962.
Tags: printf
END%%
%%ANKI
Basic
How does the precision field affect "%f" parameters?
Back: Decimal values are truncated if longer than the specified precision.
Reference: “Printf,” in Wikipedia, January 18, 2024, https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962.
Tags: printf
END%%
%%ANKI
Basic
What does a negative width field value indicate?
Back: This is actually a positive width with a - (left-align) flag.
Reference: “Printf,” in Wikipedia, January 18, 2024, https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962.
Tags: printf
END%%
%%ANKI
Basic
The - printf flag overrides what default behavior?
Back: Output is right-aligned by default.
Reference: “Printf,” in Wikipedia, January 18, 2024, https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962.
Tags: printf
END%%
%%ANKI
Cloze
The {+} printf flag {prepends a plus for positive signed-numeric types}.
Reference: “Printf,” in Wikipedia, January 18, 2024, https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962.
Tags: printf
END%%
%%ANKI
Basic
The + printf flag overrides what default behavior?
Back: Nothing is prepended to positive signed-numeric types by default.
Reference: “Printf,” in Wikipedia, January 18, 2024, https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962.
Tags: printf
END%%
%%ANKI
Cloze
The {␣} printf flag {prepends a space for positive signed-numeric types}.
Reference: “Printf,” in Wikipedia, January 18, 2024, https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962.
Tags: printf
END%%
%%ANKI
Basic
The ␣ printf flag overrides what default behavior?
Back: Nothing is prepended to positive signed-numeric types by default.
Reference: “Printf,” in Wikipedia, January 18, 2024, https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962.
Tags: printf
END%%
%%ANKI
Basic
How do the + and ␣ printf flags relate to one another?
Back: Both prepend a character to positively signed-numeric types.
Reference: “Printf,” in Wikipedia, January 18, 2024, https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962.
Tags: printf
END%%
%%ANKI
Basic
What happens if both the + and ␣ printf flags are specified?
Back: The + flag takes precedence.
Reference: “Printf,” in Wikipedia, January 18, 2024, https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962.
Tags: printf
END%%
%%ANKI
Cloze
The {0} printf flag {prepends zeros for numeric types}.
Reference: “Printf,” in Wikipedia, January 18, 2024, https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962.
Tags: printf
END%%
%%ANKI
Basic
What option must be specified for the 0 printf flag to take effect?
Back: The "width" option.
Reference: “Printf,” in Wikipedia, January 18, 2024, https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962.
Tags: printf
END%%
%%ANKI
Basic
The 0 printf flag overrides what default behavior?
Back: Spaces are used to match the "width" option by default.
Reference: “Printf,” in Wikipedia, January 18, 2024, https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962.
Tags: printf
END%%
%%ANKI
Basic
How is %#g different from %g?
Back: The former always includes a decimal point and may include trailing 0s.
Reference: “Printf,” in Wikipedia, January 18, 2024, https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962.
Tags: printf
END%%
%%ANKI
Basic
How is %#f different from %f?
Back: The former always includes a decimal point.
Reference: “Printf,” in Wikipedia, January 18, 2024, https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962.
Tags: printf
END%%
%%ANKI
Basic
How is %#e different from %e?
Back: The former always includes a decimal point.
Reference: “Printf,” in Wikipedia, January 18, 2024, https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962.
Tags: printf
END%%
%%ANKI
Basic
Which printf flag can be used to ensure decimal points in the output of floating-point types?
Back: #
Reference: “Printf,” in Wikipedia, January 18, 2024, https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962.
Tags: printf
END%%
%%ANKI
Basic
How is %#o different from %o?
Back: The former prepends a 0 to the output.
Reference: “Printf,” in Wikipedia, January 18, 2024, https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962.
Tags: printf
END%%
%%ANKI
Basic
How is %#x different from %x?
Back: The former prepends a 0x to the output.
Reference: “Printf,” in Wikipedia, January 18, 2024, https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962.
Tags: printf
END%%
%%ANKI
Basic
How is %#X different from %X?
Back: The former prepends a 0X to the output.
Reference: “Printf,” in Wikipedia, January 18, 2024, https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962.
Tags: printf
END%%
%%ANKI
Cloze
%#o is to {0} as %#x is to {0x}.
Reference: “Printf,” in Wikipedia, January 18, 2024, https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962.
Tags: printf
END%%
| Length | Description |
|---|---|
hh |
int sized integer argument promoted from a char |
h |
int sized integer argument promoted from a short |
l |
long sized integer argument |
ll |
long long sized integer argument |
z |
size_t sized integer argument |
%%ANKI
Basic
Why do length modifiers for e.g. char exist?
Back: For maximum portability in the face of default argument promotions.
Reference: “Printf,” in Wikipedia, January 18, 2024, https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962.
Tags: printf
END%%
%%ANKI
Cloze
The {hh} length corresponds to the {char} type declaration.
Reference: “Printf,” in Wikipedia, January 18, 2024, https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962.
Tags: printf
END%%
%%ANKI
Cloze
The {h} length corresponds to the {short} type declaration.
Reference: “Printf,” in Wikipedia, January 18, 2024, https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962.
Tags: printf
END%%
%%ANKI
Cloze
The {l} length corresponds to the {long} type declaration.
Reference: “Printf,” in Wikipedia, January 18, 2024, https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962.
Tags: printf
END%%
%%ANKI
Cloze
The {ll} length corresponds to the {long long} type declaration.
Reference: “Printf,” in Wikipedia, January 18, 2024, https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962.
Tags: printf
END%%
%%ANKI
Cloze
The {z} length corresponds to the {size_t} type declaration.
Reference: “Printf,” in Wikipedia, January 18, 2024, https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962.
Tags: printf
END%%
| Specifier | Description |
|---|---|
d, i |
a decimal signed int |
u |
a decimal unsigned int |
x, X |
a hexadecimal unsigned int |
o |
an octal unsigned int |
f, F |
a double in fixed-point notation |
e, E |
a double in standard notation |
g, G |
a double in normal or standard notation |
s |
a NUL-terminated string |
c |
a char character |
p |
void* address in an implementation-defined format |
%%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.
Tags: printf
END%%
%%ANKI
Basic
Why is printf named the way it is?
Back: It stands for print formatted.
Reference: “Printf,” in Wikipedia, January 18, 2024, https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962.
Tags: printf
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.
Tags: printf
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.
Tags: printf
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.
Tags: printf
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.
Tags: printf
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.
Tags: printf
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.
Tags: printf
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.
Tags: printf
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.
Tags: printf
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.
Tags: printf
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.
Tags: printf
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.
Tags: printf
END%%
%%ANKI
Cloze
The {%f} format specifier outputs a {lowercase fixed-point double}.
Reference: “Printf,” in Wikipedia, January 18, 2024, https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962.
Tags: printf
END%%
%%ANKI
Cloze
The {%F} format specifier outputs an {uppercase fixed-point double}.
Reference: “Printf,” in Wikipedia, January 18, 2024, https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962.
Tags: printf
END%%
%%ANKI
Basic
What distinguishes format specifiers %f and %F?
Back: The former outputs lowercase identifiers, the latter uppercase.
Reference: “Printf,” in Wikipedia, January 18, 2024, https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962.
Tags: printf
END%%
%%ANKI
Basic
What three special identifiers might specifier %f output?
Back: inf, infinity, and nan
Reference: “Printf,” in Wikipedia, January 18, 2024, https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962.
Tags: printf
END%%
%%ANKI
Basic
Assuming round-to-even, what is the output of printf("%.0f", 3.5)?
Back: 4
Reference: Bryant, Randal E., and David O'Hallaron. Computer Systems: A Programmer's Perspective. Third edition, Global edition. Always Learning. Pearson, 2016.
Tags: printf
END%%
%%ANKI
Basic
Assuming round-to-even, what is the output of printf("%.0f", 2.5)?
Back: 2
Reference: Bryant, Randal E., and David O'Hallaron. Computer Systems: A Programmer's Perspective. Third edition, Global edition. Always Learning. Pearson, 2016.
Tags: printf
END%%
%%ANKI Basic How does the C standard define the rounding mode of floating-point specifiers? Back: This is implementation specific. Reference: Bryant, Randal E., and David O'Hallaron. Computer Systems: A Programmer's Perspective. Third edition, Global edition. Always Learning. Pearson, 2016. Tags: printf
END%%
%%ANKI Basic What does the rounding mode of floating-point specifiers refer to? Back: How numbers with greater than the specified precision are output. Reference: Bryant, Randal E., and David O'Hallaron. Computer Systems: A Programmer's Perspective. Third edition, Global edition. Always Learning. Pearson, 2016. Tags: printf
END%%
%%ANKI
Basic
What three special identifiers might specifier %F output?
Back: INF, INFINITY, and NAN
Reference: “Printf,” in Wikipedia, January 18, 2024, https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962.
Tags: printf
END%%
%%ANKI
Basic
Which format specifier was probably used to yield printf output inf?
Back: %f
Reference: “Printf,” in Wikipedia, January 18, 2024, https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962.
Tags: printf
END%%
%%ANKI
Cloze
{1:Fixed-point} notation is to {2:%f} whereas {2:standard/exponential} notation is to {1:%e}.
Reference: “Printf,” in Wikipedia, January 18, 2024, https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962.
Tags: printf
END%%
%%ANKI
Basic
Which format specifier was probably used to yield printf output 172.345000?
Back: %f
Reference: “Printf,” in Wikipedia, January 18, 2024, https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962.
Tags: printf
END%%
%%ANKI
Basic
What term describes the kind of output notation corresponding to %f?
Back: Fixed-point notation.
Reference: “Printf,” in Wikipedia, January 18, 2024, https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962.
Tags: printf
END%%
%%ANKI
Basic
What distinguishes format specifiers %e and %E?
Back: The former outputs an e, the latter an E.
Reference: “Printf,” in Wikipedia, January 18, 2024, https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962.
Tags: printf
END%%
%%ANKI
Basic
How many digits follows e in the output of printf specifier %e?
Back: At least 2.
Reference: “Printf,” in Wikipedia, January 18, 2024, https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962.
Tags: printf
END%%
%%ANKI
Basic
Which format specifiers correspond to scientific notation?
Back: %e and %E
Reference: “Printf,” in Wikipedia, January 18, 2024, https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962.
Tags: printf
END%%
%%ANKI
Basic
Which format specifier was probably used to yield printf output 1.723450e+02?
Back: %e
Reference: “Printf,” in Wikipedia, January 18, 2024, https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962.
Tags: printf
END%%
%%ANKI
Basic
What is the default precision of %f?
Back: 6
Reference: “Printf,” in Wikipedia, January 18, 2024, https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962.
Tags: printf
END%%
%%ANKI
Basic
What is the output of printf("%e", 3.14)?
Back: 3.140000e00
Reference: “Printf,” in Wikipedia, January 18, 2024, https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962.
Tags: printf
END%%
%%ANKI
Basic
What is the output of printf("%e", 314)?
Back: 3.140000e02
Reference: “Printf,” in Wikipedia, January 18, 2024, https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962.
Tags: printf
END%%
%%ANKI
Basic
What term describes the kind of output notation corresponding to %e?
Back: Standard or exponential notation.
Reference: “Printf,” in Wikipedia, January 18, 2024, https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962.
Tags: printf
END%%
%%ANKI
Basic
What is the default precision of %e?
Back: 6
Reference: “Printf,” in Wikipedia, January 18, 2024, https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962.
Tags: printf
END%%
%%ANKI
Cloze
The {%g} format specifier outputs a {lowercase double in fixed-point or standard notation}.
Reference: “Printf,” in Wikipedia, January 18, 2024, https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962.
Tags: printf
END%%
%%ANKI
Cloze
The {%G} format specifier outputs an {uppercase double in fixed-point or standard notation}.
Reference: “Printf,” in Wikipedia, January 18, 2024, https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962.
Tags: printf
END%%
%%ANKI
Basic
The %g format specifier subsumes functionality of what other format specifiers?
Back: %f and %e
Reference: “Printf,” in Wikipedia, January 18, 2024, https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962.
Tags: printf
END%%
%%ANKI
Basic
The %G format specifier subsumes functionality of what other format specifiers?
Back: %F and %E
Reference: “Printf,” in Wikipedia, January 18, 2024, https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962.
Tags: printf
END%%
%%ANKI
Basic
How does %g handle integral values differently from %f?
Back: It excludes a trailing . and insignificant 0s.
Reference: “Printf,” in Wikipedia, January 18, 2024, https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962.
Tags: printf
END%%
%%ANKI
Basic
How does %g handle non-integral values differently from %f?
Back: It excludes insignifant 0s after the decimal point.
Reference: “Printf,” in Wikipedia, January 18, 2024, https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962.
Tags: printf
END%%
%%ANKI
Basic
What distinguishes %g from %G?
Back: The former uses lowercase letters. The latter uses uppercase letters.
Reference: “Printf,” in Wikipedia, January 18, 2024, https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962.
Tags: printf
END%%
%%ANKI
Basic
What is the output of printf("%.1f", 2.0)?
Back: 2.0
Reference: “Printf,” in Wikipedia, January 18, 2024, https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962.
Tags: printf
END%%
%%ANKI
Basic
Assuming fixed-point notation, what is the output of printf("%.1g", 2.0)?
Back: 2
Reference: “Printf,” in Wikipedia, January 18, 2024, https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962.
Tags: printf
END%%
%%ANKI
Basic
Assuming fixed-point notation, what is the output of printf("%g", 3.14)?
Back: 3.14
Reference: “Printf,” in Wikipedia, January 18, 2024, https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962.
Tags: printf
END%%
%%ANKI
Basic
Assuming fixed-point notation, what is the output of printf("%g", 3)?
Back: 3
Reference: “Printf,” in Wikipedia, January 18, 2024, https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962.
Tags: printf
END%%
%%ANKI
Basic
What is the output of printf("%f", 3)?
Back: 3.000000
Reference: “Printf,” in Wikipedia, January 18, 2024, https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962.
Tags: printf
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.
Tags: printf
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.
Tags: printf
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.
Tags: printf
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.
Tags: printf
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.
Tags: printf
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.
Tags: printf
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.
Tags: printf
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.
Tags: printf
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.
Tags: printf
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.
Reference: Bryant, Randal E., and David O'Hallaron. Computer Systems: A Programmer's Perspective. Third edition, Global edition. Always Learning. Pearson, 2016.
Tags: printf
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
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
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.
Tags: printf
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.
Tags: printf
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
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
END%%
Escape Sequences
C has a standard for processing different escape sequences. Many languages built with C in mind parse these escape sequences in a similar way.
\ooo: Consists of one to three octal digits.- bash/index supports this sequence as
$'\ooo'.
- bash/index supports this sequence as
%%ANKI
Basic
How are C escape sequences for octal digits denoted?
Back: As \ooo.
Reference: Brian W. Kernighan and Dennis M. Ritchie, The C Programming Language, 2nd ed (Englewood Cliffs, N.J: Prentice Hall, 1988).
END%%
%%ANKI
Basic
In C, \ooo allows specifying how many octal digits?
Back: One to three.
Reference: Brian W. Kernighan and Dennis M. Ritchie, The C Programming Language, 2nd ed (Englewood Cliffs, N.J: Prentice Hall, 1988).
END%%
%%ANKI
Basic
How are C escape sequences exposed in bash?
Back: Using ANSI-C quoting, i.e. $$'string'.
Reference: Mendel Cooper, “Advanced Bash-Scripting Guide,” n.d., 916.
Tags: bash
END%%
\xhh: Consists of one or more radices#Hexadecimal digits. Thexprefix is required to distinguish from octal escape sequences.- bash/index supports this sequence as
$'\xhh'. One or two digits is supported.
- bash/index supports this sequence as
%%ANKI
Basic
How are C escape sequences for hexadecimal digits denoted?
Back: As \xhh.
Reference: Brian W. Kernighan and Dennis M. Ritchie, The C Programming Language, 2nd ed (Englewood Cliffs, N.J: Prentice Hall, 1988).
END%%
%%ANKI
Basic
In C, \x allows specifying how many hexadecimal digits?
Back: One or more.
Reference: Brian W. Kernighan and Dennis M. Ritchie, The C Programming Language, 2nd ed (Englewood Cliffs, N.J: Prentice Hall, 1988).
END%%
%%ANKI
Basic
What footgun does C's \x sequence expose?
Back: Using more than two hexadecimal digits can produce undefined results.
Reference: Arnold D. Robbins, “GAWK: Effective AWK Programming,” October 2023, https://www.gnu.org/software/gawk/manual/gawk.pdf.
END%%
\uhhhh: Introduced in C11 to represent Unicode code points. Must have exactly four hexadecimal characters specified with0leading padding if necessary.- bash/index supports this sequence as
$'uhhhh'. One to four hex digits is supported.
- bash/index supports this sequence as
%%ANKI
Basic
What two ways are C escape sequences for unicode denoted?
Back: As \uhhhh or \Uhhhhhhhh.
Reference: Jens Gustedt, Modern C (Shelter Island, NY: Manning Publications Co, 2020).
Tags: encoding::unicode
END%%
%%ANKI
Basic
In C, \u allows specifying how many hexadecimal digits?
Back: Exactly four.
Reference: Jens Gustedt, Modern C (Shelter Island, NY: Manning Publications Co, 2020).
Tags: encoding::unicode
END%%
%%ANKI
Basic
In what standard were C's \u and \U escape sequences introduced?
Back: C11.
Reference: Jens Gustedt, Modern C (Shelter Island, NY: Manning Publications Co, 2020).
Tags: encoding::unicode
END%%
\Uhhhhhhhh: Introduced in C11 to represent larger unicode code points. Must have exactly eight hexadecimal characters specified with0leading padding if necessary.
%%ANKI
Basic
In C, \U allows specifying how many hexadecimal digits?
Back: Exactly eight.
Reference: Jens Gustedt, Modern C (Shelter Island, NY: Manning Publications Co, 2020).
Tags: encoding::unicode
END%%
%%ANKI
Basic
Why does C have both \u and \U?
Back: \U accommodates for larger code point values.
Reference: Jens Gustedt, Modern C (Shelter Island, NY: Manning Publications Co, 2020).
Tags: encoding::unicode
END%%
Bibliography
- Arnold D. Robbins, “GAWK: Effective AWK Programming,” October 2023, https://www.gnu.org/software/gawk/manual/gawk.pdf.
- Brian W. Kernighan and Dennis M. Ritchie, The C Programming Language, 2nd ed (Englewood Cliffs, N.J: Prentice Hall, 1988).
- Bryant, Randal E., and David O'Hallaron. Computer Systems: A Programmer's Perspective. Third edition, Global edition. Always Learning. Pearson, 2016.
- Jens Gustedt, Modern C (Shelter Island, NY: Manning Publications Co, 2020).
- Mendel Cooper, “Advanced Bash-Scripting Guide,” n.d., 916.
- “Printf,” in Wikipedia, January 18, 2024, https://en.wikipedia.org/w/index.php?title=Printf&oldid=1196716962.