Topic 7 - Basic Types

Question 1

The leftmost bit of a SIGNED integer is:

Answer 1

0 if number is positive or zero

1 if number is negative

Question 2

The largest 16-bit signed integer is:

Answer 2

2^15 - 1

Question 3

The largest 32-bit signed integer is:

Answer 3

2^31 - 1

Question 4

An integer with no sign bit is said to be:

Answer 4

unsigned

Question 5

largest 16 bit unsigned integer is:

Answer 5

2^16 - 1

Question 6

largest 32 bit unsigned integer is:

Answer 6

2^32 - 1

Question 7

By default, what type of integers are integer variables?

Answer 7

Signed integers.

Question 8

How many bits is the int type usually?

Answer 8

32 bits

Question 9

How do you tell the compiler that a variable has no sign bit?

Answer 9

declare it as unsigned.

Question 10

Decimal constants contain digits between___ and

must / must not begin with___

Answer 10

0 and 9

must not begin with a zero

Question 11

Octal constants contain digits between___ and

must / must not begin with___

Answer 11

0 and 7

must begin with a zero

Question 12

Hexadecimal constants contain digits between___ and

letters between a and f must begin with ___

Answer 12

0 and 9
0x or 0X:
0xf
0xff
0X7fff

Question 13

The letters in a hexadecimal constant may be _____

Answer 13

either upper or lower case

Question 14

How do you force the compiler to treat a constant as a long integer?

Answer 14

with the letter L or l:
15L
0x7fffL

Question 15

How do you force the compiler to treat a constant as an unsigned integer?

Answer 15

follow it with the letter U or u:
15U
0x7fffU

Question 16

What is the term that describes the event where arithmetic operations performed on integers results in a number too large to be represented as an int( because it requires too many bits)?

Answer 16

Overflow

Question 17

How do you read or write an unsigned decimal integer? (ie. when using scanf or printf)?

Answer 17

Use the letter “u” instead of “d” as a conversion specifier.

Question 18

How do you read or write an unsigned octal integer? (ie. when using scanf or printf)?

Answer 18

“o” instead of “d”

Question 19

How do you read or write an unsigned hexadecimal integer? (ie. when using scanf or printf)?

Answer 19

“x” instead of “d”

Question 20

How do you read or write a short integer? (ie. when using scanf or printf)?

Answer 20

“h” in front of d, u, o, x in the conversion specification:

scanf(“%hd”, &i);

Question 21

How do you read or write a long integer? (ie. when using scanf or printf)?

Answer 21

“l” (letter L) in front of d, u, o, or x in the conversion specification:
scanf(“%ld”, &i);

Question 22

C provides how many floating types?

Answer 22

3 types

Question 23

What are the types of floating types?

Answer 23

float - single-precision floating-point
double - double-precision floating-point
long double - extended-precision floating-point

Question 24

State the usefulness of each of the floating types:

Answer 24

float - suitable when the amount of precision is not critical
double - provides enough precision for most programs
long double - rarely used

Question 25

What does C standard state on how much precision the 3 types have?

Answer 25

C standard does not state how much precision the float, double and long double types provide, since that depends on how numbers are stored.

Question 26

What is the 2 primary formats for floating-point numbers in IEE standard 765:

Answer 26

1) single-precision (32 bits)

2) double-precision (64 bits)

Question 27

How are numbers stored when stored as a floating point??

Answer 27

number = sign x fraction x 2^exponent

Question 28

Single-precision format: how many bits long?

Answer 28

exponent: 8 bits
fraction: 23 bits

Question 29

double-precision format: how many bits long?

Answer 29

exponent: 11 bits
fraction: 52 bits

Question 30

By default, floating constants are stored as?

Answer 30

double-precision numbers

Question 31

How do you indicate that only single precision is desired when storing a constant?

Answer 31

put the letter f or F at the end of the constant ie. 57.9F

Question 32

A floating constant must contain:

Answer 32

a decimal point or an exponent (or both)

Question 33

What are the conversion specifiers %e, %f and %g’s precision?

Answer 33

Used to read/write single-precision.

Question 34

How do you force read a value of type double?

Answer 34

put an “l” in front of f or e or g:

scanf(“%lf”, &d);

Question 35

How many bytes does a char consume?

Answer 35

A single byte.

Question 36

Signed characters have values between:

Answer 36

-128 and 127

Question 37

Unsigned characters have values between:

Answer 37

0 and 255

Question 38

What function can you use to convert a character to its upper-case counterpart?

Answer 38

#include 
ch = toupper(ch)

Question 39

What’s the conversion specification for scanf and printf to read and write single characters:

Answer 39

“%c”

Question 40

Does scanf skip white-space characters as usual when reading %c?

Answer 40

No

Question 41

How do you force scanf to skip white-space characters?

Answer 41

put a space in its format string before the %c:

scanf(“ %c”, &ch);

Question 42

For reading and writing a single character, what is an alternative function to scanf/printf?

Answer 42

putchar and getchar:
putchar(ch);
ch = getchar();

Question 43

Does getchar skip white-spaces?

Answer 43

No

Question 44

Write a statement that uses getchar to skip an indefinite number of blank characters

Answer 44

while ((ch = getchar()) == ‘ ‘)
;
when the loop terminates, the ch will contain the first nonblank character that getchar encountered

Question 45

What are the requirements of the two operands to perform an arithmetic operation?

Answer 45

They must be the same size ie. same number of bits.

Stores in the same way.

Question 46

What is an implicit conversion?

Answer 46

When the compiler matches the types of 2 operands that are having arithmetic or logical operations being performed on them - the smaller sized type gets casted to the 2nd operand’s type so precision isn’t lost

Question 47

What are the 4 cases in which implicit conversion is carried out by the compiler?

Answer 47

1) unmatched operands in an arithmetic or logical operation
2) assignment type mismatch with variable type
3) input type mismatch with function’s argument type
4) return statement returning value of mismatched type with argument’s return type

Question 48

What are the 2 cases for performing the usual arithmetic conversions?

Answer 48

1) the type of other operand is a floating type

2) neither operand type is a floating type

Question 49

Can you force implicit conversions?

Answer 49

Yes.

Question 50

What does C regard ( type-name) as?

Answer 50

A unary operator (which has higher precedence than binary operators)

Question 51

What type is returned by sizeof operator?

Answer 51

An unsigned integer representing the number of bytes required to store a value belonging to type-name