Arrays, Strings, Randomness and Pointers

Question 1

What is an example of signed int overflow in C?

Answer 1

When unsigned short int x = 65535; is assigned to short int y, y becomes -1.

Question 2

What is the output of printf for variable c when c = x; with x = 65535?

Answer 2

Undefined behaviour.

Question 3

What are the two types of arrays in C?

Answer 3

• 1D arrays
• 2D arrays

Question 4

What does C not do with respect to arrays?

Answer 4

C does not perform bounds checking.

Question 5

How are strings represented in C?

Answer 5

Strings are arrays of characters ending with a null terminator (0).

Question 6

What does the function strlen(s) do in C?

Answer 6

Returns the length of the string (excluding the null terminator).

Question 7

What is the purpose of srand(seed) in C?

Answer 7

Sets a new seed to change the sequence of random numbers.

Question 8

What does the function rand() generate?

Answer 8

A pseudo-random integer between 0 and RAND_MAX.

Question 9

What is the shape of the Normal (Gaussian) Distribution?

Answer 9

Follows a bell-curve shape.

Question 10

What does the GNU Scientific Library (GSL) provide?

Answer 10

Better random number generators than rand().

Question 11

What is the purpose of the function gsl_rng_set in GSL?

Answer 11

Sets the seed for the random number generator.

Question 12

Fill in the blank: Strings in C are just arrays of characters ending with a ______.

Answer 12

null terminator.

Question 13

True or False: C automatically checks for buffer overflows in arrays.

Answer 13

False.

Question 14

What is the output of printf when using sprintf(buffer, “%s %d”, str, num)?

Answer 14

Formats and stores output into buffer.

Question 15

What is a one-dimensional array in C?

Answer 15

An array that holds a fixed number of elements of the same type, initialized with specific values.

Question 16

How can the size of an array be defined in C?

Answer 16

The size can be implicit and defined by its initialization.

Question 17

What is an uninitialized array in C?

Answer 17

An array declared without an initial value, containing random data.

Question 18

How is a two-dimensional array initialized in C?

Answer 18

An array of arrays initialized with specific values.

Question 19

How do you access and set individual values in an array?

Answer 19

Using index notation, e.g., anArray[0] = 42; or array[3] = ‘Z’;

Question 20

What is a string in C?

Answer 20

A string is an array of characters terminated by a null character (0).

Question 21

What is the significance of the null terminator in strings?

Answer 21

It signals the end of the string to prevent the program from getting stuck.

Question 22

True or False: Strings in C are enclosed in single quotes.

Answer 22

False.

Question 23

What are functions in C?

Answer 23

Uniquely named groups of program statements that may accept parameters and return values.

Question 24

What is the syntax for defining a function in C?

Answer 24

<return> functionName(<parameter>) { /* statements */ return <value>; }
</value></parameter></return>

Question 25

What is the main function requirement in a C program?

Answer 25

Every program must include a main() function.

Question 26

What is a procedure in C?

Answer 26

A function that does not return a value, defined with void.

Question 27

What is the purpose of function prototypes?

Answer 27

To inform the compiler of the function’s signature before it is called.

Question 28

What is the difference between global and local scope?

Answer 28

Global variables are declared outside functions, while local variables exist only within the function.

Question 29

What are static variables in C?

Answer 29

Variables that are initialized only once and retain their value between function calls.

Question 30

Fill in the blank: Functions must have a _______ name.

Answer 30

unique.

Question 31

What should be avoided unless necessary in function design?

Answer 31

Using global variables.

Question 32

What are the key points regarding functions in C?

Answer 32

* Define using a clear structure and unique names * Avoid overloading; separate by purpose and return type * Use prototypes to declare functions before use * Avoid global variables unless justified * Utilize static variables for data persistence

Question 33

What fundamentals were covered in this lecture?

Answer 33

Defining and using functions, role of prototypes, scope, and static variables.

Question 34

What is stored in memory?

Answer 34

Every variable.

Question 35

What does each memory location have?

Answer 35

An address (a numerical label).

Question 36

How many bytes are typically allocated for an integer variable?

Answer 36

4 bytes.

Question 37

What is a pointer?

Answer 37

A variable that stores a memory address instead of a value.

Question 38

How do you declare a pointer to a character?

Answer 38

char *p;

Question 39

What does the & operator do?

Answer 39

Gives the address of a variable.

Question 40

What does the * operator do?

Answer 40

Dereferences a pointer to access the value at the stored memory address.