Week 2: C Fundamentals

Question 1

What are the two main ways of changing programs to machine language?

Answer 1

Compilers and Interpreters

Question 2

What is source code?

Answer 2

Code written in a programming language by a developer

Question 3

What is a compiler?

Answer 3

A computer program that transforms code from one format to another (needs a different compiler depending on what system you are using)

Question 4

What is an interpreter?

Answer 4

A program that translates and executes code, usually translates and executes source code line by line. There is no object code written as an intermediary

Question 5

What is primary and secondary memory?

Answer 5

Primary memory: mechanism to present memory to the CPU, is temporary

Secondary memory: stores memory, is permanent

Question 6

What is C?

Answer 6

A general purpose, procedural computer programming language supporting structured programming, lexical variable scope, and recursion, with a static type system

Question 7

Who developed C?

Answer 7

Bell Labs: Ken Thompson, Dennis Ritchie, and others

Question 8

Why was C originally developed?

Answer 8

To design and support Unix operating system

Question 9

Benefits of C:

Answer 9

• Intended as a language for programmers
• Powerful and efficient
• Structured
• Standardized

Question 10

What three steps are necessary for a program to be executed?

Answer 10

Preprocessing, compiling, and linking

Question 11

What is preprocessing?

Answer 11

Finds and deals with processing commands (directives) starting with a #

Question 12

What is compiling?

Answer 12

Translating the program into machine instructions

Question 13

What is linking?

Answer 13

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

Question 14

What is the UNIX compile command and its syntax? (For C)

Answer 14

gcc

Syntax: { gcc -o nameOfExecutable program.c }

Question 15

What are the three key language features of C?

Answer 15

• Directives
• Functions
• Statements

Question 16

What do directives always begin with?

Answer 16

#

Question 17

Do directives end with a semicolon or any other special marking?

Answer 17

NO

Question 18

What are directives?

Answer 18

Commands intended for the preprocessor

Question 19

What are functions?

Answer 19

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

Question 20

What does a function end with

Answer 20

Usually a return statement

Question 21

What is the mandatory function?

Answer 21

main

Question 22

What should the main function return?

Answer 22

A status code, 0 indicates normal termination

Question 23

What is a statement?

Answer 23

A command to be executed when the code runs

Question 24

C requires each statement to end with a

Answer 24

; semicolon

Question 25

What are the two formats for comments?

Answer 25

/\* comment \*/ or ``` // comment // more comment ```

Question 26

Each variable must have a

Answer 26

type

Question 27

All variables must be... before use

Answer 27

Declared

Question 28

When main declares variables, they must...

Answer 28

precede statements

Question 29

Variable initialization is also known as

Answer 29

Defining

Question 30

What does this do? int height = 8, length = 12, width = 10;

Answer 30

Declares three ints and initializes them

Question 31

What does this do? int height, length, width = 10;

Answer 31

Declares three ints but initializes only width

Question 32

Initializing a float requires what? Where?

Answer 32

an f at the end of the constant profit = 2150.48f;

Question 33

Macro definitions are typically

Answer 33

Containing only upper-case letters #define RECIPROCAL\_OF\_PI (1.0f / 3.14159f)

Question 34

Identifiers (name for a variable) must

Answer 34

Begin with a letter or underscore

Question 35

Identifiers can contain:

Answer 35

Can contain letters, digits, and underscores ONLY

Question 36

Are identifiers case-sensitive?

Answer 36

Yes

Question 37

Keywords must:

Answer 37

contain only lowercase letters

Question 38

What are the steps for compiling a program?

Answer 38

Step 1: Write the source codes and header files Step 2: Pre-process the source codes according to the preprocessor directives Step 3: Compile the pre-processed source codes into object codes Step 4: Link the compiled object codes with other object codes to produce the executable code Step 5: Load the executable code into computer memory Step 6: Run the executable code

Question 39

What is the syntax of a switch statement?

Answer 39

switch (input) { case 1: statement; break; case 2: statement; break; default: statement; break; } Default is the equivalent of an "else"

Question 40

What is the difference between a while loop and a do-while loop?

Answer 40

While loops pre-test the condition Do-while loops post test the condition

Question 41

What is the order of events in a for-loop?

Answer 41

a-b c-b c-b c-b

Question 42

What is the format of the conditional ? operator

Answer 42

(condition) ? expression1 : expression2 If the condition evaluates to true, expression1 is executed, if the condition evaluates to false, expression2 is evaluated