Topic 2 - C Fundamentals

Question 1

Sime C programs have the form:

Answer 1

directives
int main(void)
{
   statements
}

Question 2

Every C program relies on 3 key language features:

Answer 2

1) Directives
2) Functions
3) Statements

Question 3

Before a program can be executed, three steps are usually necessary:

Answer 3

1) Preprocessing
2) Compiling
3) Linking

Question 4

Define: Preprocessing:

Answer 4

The preprocessor obeys commands that begin with # (known as directives)

Question 5

Define: Compiling:

Answer 5

A compiler translates the program into machine instructions (object code)

Question 6

Define: Linking

Answer 6

A linker combines the object code produced by the compiler with any additional code needed to yield a complete executable program

Question 7

Compiling and Linking: The _____ and _____ are usually integrated within the _____.

Answer 7

preprocessor; linker; compiler.

Question 8

With filenames for C, is the .c extension required or not.

Answer 8

Required

Question 9

To compile and link a program called pun.c under Unix, enter the following command in a terminal at command-line promo:

Answer 9

cc pun.c

Question 10

What is automatically done when “cc” is invoked?

Answer 10

Preprocessing and linking are automatic when using cc.

Question 11

After compiling and linking the program, what happens?

Answer 11

cc leaves the executable program in a file named a.out by default

Question 12

What does -o option do

Answer 12

choose the name of the file containing the executable program

Question 13

Give the command to choose the name “pun” for the output file when you compile the program pun.c

Answer 13

cc -o pun pun.c
or
cc pun.c -o pun

Question 14

What happens before a C program is compiled?

Answer 14

It is first edited by a preprocessor.

Question 15

Commands intended fro the preprocessor are called ______

Answer 15

Directives

Question 16

What character do directives start with?

Answer 16

A hashtag (#) character

Question 17

Examples of directives:

Answer 17

include

Question 18

What is

Answer 18

A header containing information aboutC’s standard I/O library

Question 19

By default, each directive is how many lines long?

Answer 19

One line long

Question 20

Are there any semicolons besides directives?

Answer 20

No and no other special marker at the end either

Question 21

What is a function?

Answer 21

A series of statements that have been grouped together and given a name

Question 22

A function that computes a value uses a____

Answer 22

return statement to specify what value it returns

Question 23

What gets called automatically when a C program you’ve made is executed?

Answer 23

The Main function

Question 24

What does the main return?

Answer 24

A Status code

Question 25

Is the status code that’s retuned by a Unix shell script similar to the status code retuned by a Unix shells script?

Answer 25

Yes

Question 26

What is the status code returned by main when a program normally terminates after finishing?

Answer 26

0

Question 27

Will you run into problems if there’s no return statement at end of main function?

Answer 27

Yes, warning message.

Question 28

When printing strings with printf function, does the curse automatically advance the cursor one line?

Answer 28

No, you have to include the \n in the string to be printed

Question 29

How do you comment?

Answer 29

/* and ends with */

Question 30

Variables must be ______ before they are used.

Answer 30

Declared

Question 31

Can several variables be declared at the same time?

Answer 31

Yes:

int height, length, width, volume

Question 32

In C99, how can you comment?

Answer 32

// this is a commend ended at the end of the line

Question 33

When main function contains declarations, where must they be placed?

Answer 33

Must precede ANY statements.

Question 34

In C99, declarations don’t have to come before statements

Answer 34

Yet, variable must be declared before they are used

Question 35

Can you assign value of certain type into a variable of a different type?

Answer 35

It is possible but not always safe.

Question 36

Explain the different parts to this statement:

printf ( “Height: %d\n”, height );

Answer 36

• printf is being used to display the current value of a variable
• %d is a placeholder indicating where the value of the variable height is to be filled in

Question 37

What type of variables does %d work on?

Answer 37

only int variables

Question 38

How do you print float variables since you cannot use %d with float?

Answer 38

Use %f instead.

Question 39

%f prints how many decimals?

Answer 39

6 decimals.

Question 40

profit = 2150.48f;
printf(“Profit: $ \n”, profit);
What goes in the space to print only 2 decimals of the profit value instead of 6?

Answer 40

%.2f

Question 41

Can an initial value of a variable be included in its declaration?

Answer 41

Yes, called the “initializer” ex:
int height = 8, length = 12, width = 10;
int height, length, width = 10;

Question 42

How do you scan an int value stored in variable “i”?

Answer 42

scant (“%d”, &i)

Question 43

How do you scan a float value stored in variable “x”?

Answer 43

scanf(“%f”, &x);

Question 44

What are macro definitions?

Answer 44

Name a constant - ex:
#define INCHES_PER_POUND 166

Question 45

When a program is compiled, what is replacing each macro by the value it represents?

Answer 45

The Preprocessor

Question 46

Duringpreprocessing,thestatement
weight = (volume + INCHES_PER_POUND - 1) / INCHES_PER_POUND;
will become

Answer 46

weight = (volume + 166 - 1) / 166;

Question 47

Names for variables, functions, macros, and other entities are called _____

Answer 47

identifiers

Question 48

identifiers must being with a

Answer 48

letter or underscore (i.e. no numbers)

Question 49

Is C case-sensitive?

Answer 49

Yes

Question 50

What is the limit on the maximum length of an identifier?

Answer 50

C places no limit; none.

Question 51

The following keywords can’t be used as identifiers:

Answer 51

auto enum restrict unsigned break extern return void
case float
char for
const goto
continue if
default inline struct _Imaginary do int switch
double    long      typedef
else      register  union
short
signed
sizeof
static
volatile
while

Question 52

The following keywords can’t be used as identifiers (C99 only):

Answer 52

inline; restrict; _Bool; _Complex; _Imaginary

Question 53

A c program is a series of _____

Answer 53

tokens

Question 54

Give examples of tokens:

Answer 54

- identifiers
keywords
operators
punctuations
constants
string literals

Question 55

How many tokens are in:

printf(“Height: %d\n”, height);

Answer 55

7:
printf - identifier
( - punctuation
"Height: %d\n" - string literal
, - punctuation
height - identifier
) - punctuation
; - punctuation

Question 56

How important is the amount of space between tokens usually?

Answer 56

Usually not critical.

Question 57

Can you put a new-line character in a string over two lines?

Answer 57

No its illegal