C/C++ Programming Language

Question 1

Makefiles

Answer 1

Yeah

Question 2

Relational Operator “>”

Answer 2

Greater Than

Question 3

malloc( ) and calloc( ) functions, what are they and how are they different?

Answer 3

malloc( ) and calloc( ) are library functions that allocate memory dynamically. Accomplished using heap segmenting. Both functions return pointers to the beginning of the memory , or NULL if the allocation failed.

malloc( ) allocates a memory block of a given size (in bytes) and returns a pointer to the beginning of the block. The memory, however, is not initialized. If we try to access the content of the memory block then we’ll get garbage values.

calloc( ) allocates AND initializes memory blocks to zero. Additionally, calloc takes two arguments, the number of blocks to be allocated, and the size of each block.

In either case, any use of these functions must be followed with a call of free( ) in order to deallocate the memory, else you have a memory leak.

Question 4

The form of the “if” conditional statement

Answer 4

if(condition){statements}

Question 5

4 phases of code development

Answer 5

1.Code 2.Save 3.Compile 4.Execute

Question 6

The “Stack” As it pertains to the C language

Answer 6

Stack is a memory region where “local variables”, “return addresses of function calls” and “arguments to functions” are hold while C program is executed. CPU’s current state is saved in stack memory

Question 7

Relational Operator “<=”

Answer 7

Less than or Equal To

Question 8

calloc

Answer 8

Yeah?

Question 9

Relational Operator “!=”

Answer 9

Not Equal To

Question 10

Relational Operator “>=”

Answer 10

Greater than or equal to

Question 11

Relational Operator “

Answer 11

Less Than

Question 12

string

Answer 12

A string is a sequence of characters, more specifically it is an array of characters.

Question 13

char

Answer 13

Used to specify individual characters (also bytes sometimes as they are only a single byte)

Question 14

The “Heap” as it pertains to the C language

Answer 14

Heap is a memory region which is used by dynamic memory allocation functions at run time. Linked list is an example which uses heap memory.

Question 15

int

Answer 15

used to specify integer data types.

Question 16

What does a Compiler do

Answer 16

A Compiler converts human readable code into machine code.

Question 17

double

Answer 17

Used top specify double precision floating point numbers

Question 18

Relational Operator “==”

Answer 18

Equal To

Question 19

Semaphore

Answer 19

Semaphore is a signaling mechansm (“I am done, you can carry on” kind of signal). For example, if you are listening to songs (assume it as one task) on your mobile and at the same time your friend calls you, an interrupt is triggered upon which an ISR signals the call processing task to wakeup.

A semaphore is a generalized mutex. In lieu of single buffer, we can split the 4 KB buffer into four 1 KB buffers (identical resources). A semaphore can be associated with these four buffers. The consumer and producer can work on different buffers at the same time.

Question 20

free () -memory

Answer 20

Yeah?

Question 21

What will the following command do? g++ helloworld.cpp -o hw

Answer 21

This command will compile the code in “helloworld.cpp” using G++ and output it with the name hw.out.

Question 22

Mutex

Answer 22

A mutex is a locking mechanism used to synchronize access to a resource. A mutex provides mutual exculsion, either producer or consumer can have the key (mutex) and proceed with their work. As long as the buffer is filled by producer, the conusmer needs to wait, and vice versa. At any point, only one thread can work with the entire buffer.

Question 23

bool

Answer 23

Stores Boolean Data, usually specific to C and C++ in software Development. You will usually not see this in embedded programming.

Question 24

“chaining”

Answer 24

pertains to the combination of strings and variables, similar to how Python allows combinations of outpus in a print statements. This method is contingent on the use of “cout” in the iostream library.

Question 25

strdup (something to do with strings I think)

Answer 25

Yeah

Question 26

Syntax for Modulo “%” operator

Answer 26

remainder = numerator % denominator;

Question 27

What is the “#” Operator in C/C++

Answer 27

Before a C program is compiled in a compiler, source code is processed by a program called preprocessor. This process is called preprocessing. Commands used in preprocessor are called preprocessor directives and they begin with “#” symbol.