16 KiB
| title | TARGET DECK | FILE TAGS | tags | |
|---|---|---|---|---|
| Declarations | Obsidian::STEM | c17 |
|
Overview
| Signed | Unsigned | 32-bit | 64-bit |
|---|---|---|---|
| signed char | unsigned char | 1 | 1 |
| short | unsigned short | 2 | 2 |
| int | unsigned | 4 | 4 |
| long | unsigned long | 4 | 8 |
| long long | unsigned long long | 8 | 8 |
| char * | - | 4 | 8 |
| float | - | 4 | 4 |
| double | - | 8 | 8 |
Fixed width data integral types (e.g. int32_t) can be found by including <stdint.h>.
%%ANKI
Cloze
The {<stdint.h>} header file contains {fixed width data integral types}.
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
Which header file contains INT32_MAX?
Back: <stdint.h>
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 does the "width" of an integer type refer to? Back: The number of bits used to represent its value. Reference: Bryant, Randal E., and David O'Hallaron. Computer Systems: A Programmer's Perspective. Third edition, Global edition. Always Learning. Pearson, 2016.
END%%
%%ANKI What two variants does a C integral type declaration have? Back: Signed and unsigned. Reference: Bryant, Randal E., and David O'Hallaron. Computer Systems: A Programmer's Perspective. Third edition, Global edition. Always Learning. Pearson, 2016. END%%
%%ANKI What does it mean for an integer to be "signed"? Back: It can represent negative, zero, and positive values. Reference: Bryant, Randal E., and David O'Hallaron. Computer Systems: A Programmer's Perspective. Third edition, Global edition. Always Learning. Pearson, 2016. END%%
%%ANKI What does it mean for an integer to be "unsigned"? Back: It can only represent nonnegative values. 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 How large is a word? Back: This is a machine-dependent value. 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 word sizes are typical nowadays? Back: 32- and 64-bit word sizes. Reference: Bryant, Randal E., and David O'Hallaron. Computer Systems: A Programmer's Perspective. Third edition, Global edition. Always Learning. Pearson, 2016.
END%%
%%ANKI
Cloze
char typically represents {1} byte(s) on a 64-bit platform.
Reference: Bryant, Randal E., and David O'Hallaron. Computer Systems: A Programmer's Perspective. Third edition, Global edition. Always Learning. Pearson, 2016.
END%%
%%ANKI
Cloze
short typically represents {2} byte(s) on a 64-bit platform.
Reference: Bryant, Randal E., and David O'Hallaron. Computer Systems: A Programmer's Perspective. Third edition, Global edition. Always Learning. Pearson, 2016.
END%%
%%ANKI
Cloze
int typically represents {4} bytes(s) on a 64-bit platform.
Reference: Bryant, Randal E., and David O'Hallaron. Computer Systems: A Programmer's Perspective. Third edition, Global edition. Always Learning. Pearson, 2016.
END%%
%%ANKI
Cloze
unsigned typically represents {4} bytes(s) on a 64-bit platform.
Reference: Bryant, Randal E., and David O'Hallaron. Computer Systems: A Programmer's Perspective. Third edition, Global edition. Always Learning. Pearson, 2016.
END%%
%%ANKI
Cloze
long typically represents {8} bytes(s) on a 64-bit platform.
Reference: Bryant, Randal E., and David O'Hallaron. Computer Systems: A Programmer's Perspective. Third edition, Global edition. Always Learning. Pearson, 2016.
END%%
%%ANKI
Cloze
long long typically represents {8} bytes(s) on a 64-bit platform.
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 distinguishes long from long long?
Back: long longs are guaranteed to be at least 64-bit wide.
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
Why is there both a long and long long?
Back: long longs are at least 64-bit wide, even on 32-bit platforms.
Reference: Bryant, Randal E., and David O'Hallaron. Computer Systems: A Programmer's Perspective. Third edition, Global edition. Always Learning. Pearson, 2016.
END%%
%%ANKI
Cloze
char * typically represents {8} bytes(s) on a 64-bit platform.
Reference: Bryant, Randal E., and David O'Hallaron. Computer Systems: A Programmer's Perspective. Third edition, Global edition. Always Learning. Pearson, 2016.
END%%
%%ANKI
Cloze
float typically represents {4} bytes(s) on a 64-bit platform.
Reference: Bryant, Randal E., and David O'Hallaron. Computer Systems: A Programmer's Perspective. Third edition, Global edition. Always Learning. Pearson, 2016.
END%%
%%ANKI
Cloze
double typically represents {8} bytes(s) on a 64-bit platform.
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
Is declaration int signed or unsigned?
Back: Signed.
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
How is declaration unsigned written more precisely?
Back: unsigned int.
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
Is declaration long signed or unsigned?
Back: Signed.
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
Is declaration char signed or unsigned?
Back: This is implementation-dependent.
Reference: Bryant, Randal E., and David O'Hallaron. Computer Systems: A Programmer's Perspective. Third edition, Global edition. Always Learning. Pearson, 2016.
END%%
%%ANKI
Cloze
{1:float} has {2:4} byte precision whereas {2:double} has {1:8} byte precision.
Reference: Bryant, Randal E., and David O'Hallaron. Computer Systems: A Programmer's Perspective. Third edition, Global edition. Always Learning. Pearson, 2016.
END%%
%%ANKI Cloze The C standard sets {1:lower bounds} on data type ranges, but does not set {1:upper bounds} (except with fixed-size types). Reference: Bryant, Randal E., and David O'Hallaron. Computer Systems: A Programmer's Perspective. Third edition, Global edition. Always Learning. Pearson, 2016.
END%%
Integer Literals
Negative integer literals are typed in a counterintuitive way. When the compiler sees a number of form -X, the type of X is first determined before then being negated. Promotion rules are as follows:
| Decimal | Other Bases |
|---|---|
int |
int |
long |
unsigned |
long long |
long |
- |
unsigned long |
- |
long long |
- |
unsigned long long |
%%ANKI
Basic
How does the compiler process integer literal -X?
Back: By first determining the type of X and then negating the value.
Reference: 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 integer literals are guaranteed signed?
Back: Decimal integer constants.
Reference: 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
How do we specify an octal integer literal?
Back: Prepend the literal with a 0.
Reference: 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
Why avoid negative octal integer literals?
Back: Depending on value, the resulting type may be unsigned.
Reference: 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
How do we specify a hexadecimal integer literal?
Back: Prepend the literal with a 0x or 0X.
Reference: Reference: Bryant, Randal E., and David O'Hallaron. Computer Systems: A Programmer's Perspective. Third edition, Global edition. Always Learning. Pearson, 2016.
END%%
%%ANKI
Cloze
Octal literals are to {0} whereas hexadecimal literals are to {0x/0X}.
Reference: 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
How might C dangerously interpret a negative hexadecimal integer literal?
Back: Depending on the value, the resulting type may be unsigned.
Reference: 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
Which header file contains INT_MAX?
Back: <limits.h>
Reference: Bryant, Randal E., and David O'Hallaron. Computer Systems: A Programmer's Perspective. Third edition, Global edition. Always Learning. Pearson, 2016.
END%%
%%ANKI
Cloze
{INT_MAX} is to signed whereas {UINT_MAX} is to unsigned.
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
How does <limits.h> define INT_MIN?
Back: As (-INT_MAX - 1).
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
Why is INT_MIN defined as (-INT_MAX - 1) instead of directly as e.g. -2147483648?
Back: Because 2147483648 (without -) would be sized as a non-int before being negated.
Reference: Bryant, Randal E., and David O'Hallaron. Computer Systems: A Programmer's Perspective. Third edition, Global edition. Always Learning. Pearson, 2016.
END%%
%%ANKI
Cloze
INT_MAX is to {<limits.h>} whereas INT32_MAX is to {<stdint.h>}.
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 suffix can be used to denote an unsigned integer literal?
Back: Case-insensitive U.
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 suffix can be used to denote a long integer literal?
Back: Case-insensitive L.
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 suffix can be used to denote a long long integer literal?
Back: Case-insensitive LL.
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 suffix can be used to denote an unsigned long long integer literal?
Back: Case-insensitive ULL.
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 In what order does C cast size and "signedness"? Back: C casts size then signedness. 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 In what order does C cast "signedness" and size? Back: C casts size then signedness. 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
Given short sx, cast (unsigned) sx is more explicitly written as what other sequence of casts?
Back: (unsigned) (int) sx
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
Given short sx, are the following two lines equivalent?
(unsigned) sx
(unsigned) (int) sx
Back: Yes. 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
Given short sx, are the following two lines equivalent?
(unsigned) sx
(unsigned) (unsigned short) sx
Back: No. 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
Given short sx, why is the following not an identity?
(unsigned) sx = (unsigned) (unsigned short) sx
Back: (unsigned) sx casts size before "signedness".
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 does "signedness" of a variable refer to?
Back: Whether the variable was declared signed or unsigned.
Reference: Bryant, Randal E., and David O'Hallaron. Computer Systems: A Programmer's Perspective. Third edition, Global edition. Always Learning. Pearson, 2016.
END%%
Pointers
Pointers have the same size as the machine's word size since it should be able to refer to any virtual address.
%%ANKI Basic Why does a pointer's size match the machine's word size? Back: Because it should be able to refer to any virtual address. Reference: Bryant, Randal E., and David O'Hallaron. Computer Systems: A Programmer's Perspective. Third edition, Global edition. Always Learning. Pearson, 2016.
END%%
Bibliography
- Bryant, Randal E., and David O'Hallaron. Computer Systems: A Programmer's Perspective. Third edition, Global edition. Always Learning. Pearson, 2016.