notebook/notes/c17/strings.md

title	TARGET DECK	FILE TAGS	tags
Strings	Obsidian::STEM	c17	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%%

%%ANKI Basic What kind of array can be expressed as a literal? Back: Strings. Reference: Jens Gustedt, Modern C (Shelter Island, NY: Manning Publications Co, 2020).

END%%

%%ANKI Cloze A {string} is a {NUL}-terminated array of {char}. Reference: Jens Gustedt, Modern C (Shelter Island, NY: Manning Publications Co, 2020).

END%%

%%ANKI Cloze <string.h> uses prefix {mem} to refer to {array} arguments. Reference: Jens Gustedt, Modern C (Shelter Island, NY: Manning Publications Co, 2020).

END%%

%%ANKI Cloze <string.h> uses prefix {str} to refer to {string} arguments. Reference: Jens Gustedt, Modern C (Shelter Island, NY: Manning Publications Co, 2020).

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 What is the purpose of the width field in a printf argument? Back: It specifies a minimum number of characters to ouput. 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 purpose of the precision field in a printf argument? Back: It specifies the maximum limit on the output, depending on the argument type. 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 purpose of the length field in a printf argument? Back: It specifies the size of the printf argument before default promotion. 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 {1:width} and {1:precision} fields are output related whereas the {2: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 was 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 was 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 follow 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'.

%%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. The x prefix is required to distinguish from octal escape sequences.
  • bash/index supports this sequence as $'\xhh'. One or two digits is supported.

%%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 with 0 leading padding if necessary.
  • bash/index supports this sequence as $'uhhhh'. One to four hex digits is supported.

%%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 with 0 leading 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.