Lecture 2 - C Basics

Question 1

Is C object-oriented?

Answer 1

No

Question 2

What is the difference between Java and C when OOP is ignored?

Answer 2

How memory is managed and how the program is executed.

Question 3

What does -Werror do?

Answer 3

Turns all warnings into errors making the program impossible to compile until all warnings have been fixed.

Question 4

What does the -Wall flag do?

Answer 4

The -Wall flag enables most compiler warnings

Question 5

What are make files?

Answer 5

Files that allow building of C programs automatically -> with a command.

Question 6

Are make files C exclusive?

Answer 6

No, they can be used for any command line interface command.

Question 7

What is the first line of a make file made up of?

Answer 7

[targets] : [sources]
- sources can be thought of as dependencies

Question 8

What does typing make in the CLI do?

Answer 8

Execute the first command in the make file.

Question 9

What does every C program have ?

Answer 9

An entry function called main.

Question 10

Do we need to return anything from a main function?

Answer 10

No, 0 is automatically returned by the function.
0 indicates successful execution

Question 11

What does a non-negative value returned from main indicate?

Answer 11

unsuccessful execution

Question 12

What are the 2 versions of main?

Answer 12

int main() { … }
int main(int argc, char* argv[]) { … }

Question 13

What is a C programming language?

Answer 13

A statically typed language where every variable must have a data type known without running the program.

Question 14

What are data types?

Answer 14

A label which gives meaning to its stored in memory.

Question 15

What do we control when choosing a specific data type?

Answer 15

The amount of memory we use, as different data types take up different amount of space.

Question 16

How do booleans work in C?

Answer 16

0 is false and anything else is true. The data type is int.

Question 17

What do data types help with ?

Answer 17

Preserving meaning to computations and results.So only meaningful computations can be completed.

Question 18

Size of char?

Answer 18

1 byte

Question 19

Size of short / unsigned short?

Answer 19

2 bytes = 16 bits

Question 20

Size of int / unsigned int?

Answer 20

4 bytes = 32 bits

Question 21

Size of long / unsigned long?

Answer 21

4 or 8 bytes

Question 22

Size of long long / unsigned long long?

Answer 22

8 bytes

Question 23

What does the <stdbool.h> inclusion give us?</stdbool.h>

Answer 23

The ability to have a defined type of boolean (bool) in C99.
These are defined as macros

Question 24

What is a {} called in C?

Answer 24

A block

Question 25

What does {} introduce?

Answer 25

A lexical scope/

Question 26

What must be unique in a lexical scope?

Answer 26

Variable names

Question 27

What are the 3 ways of allocating variables?

Answer 27

• automatic (declared in a local block)
• static (declared at file level - outside all blocks). Lifetime is the entire execution of program.
• allocated (the ones we dynamically requested)

Question 28

Do we need to manage memory for automatic variables?

Answer 28

No, it happens automatically.

Question 29

What is a struct ?

Answer 29

Structure which consists of members which could be of different data types.

Question 30

How are members in a struct stored in memory?

Answer 30

Next to each other (sequentially)

Question 31

What does every string end with in C?

Answer 31

\0, it is added automatically

Question 32

What is a function definition?

Answer 32

fully specifies the behaviour of a function

Question 33

What is a function declaration?

Answer 33

the interface describing how a function can be used

Question 34

What searches for functions when they’re not in source file (they could be in different file or library).

Answer 34

The linker

Question 35

How are arguments passed to functions in C and what does this mean?

Answer 35

Call by value , we pass a copy of arguments to function (except arrays and pointers).