Advanced Programming in C++

Question 1

Why do we use C/C++?

Answer 1

• Complete, non-simplified
• Efficient
• Can handle high-performance tasks like simulations, real-time processing, and visualization
• Language of choice for embedded systems
• Can be made safe with proper education

Question 2

What are the main steps in the C++ compilation process?

Answer 2

• Preprocessing
• Compilation (converting source code to object code)
• Linking (combining object code with libraries to create an executable)

Question 3

What is the purpose of the preprocessing stage in C++ compilation?

Answer 3

Preprocessing handles directives like #include and #define, preparing the code for compilation

Question 4

What does the term “data type” refer to in C++?

Answer 4

A data type specifies the kind of data a variable can hold, such as int, char, or float.

Question 5

What are the main categories of primitive data types in C++?

Answer 5

• Integer Numbers (int)
• Character (char)
• Booleans (bool)
• Floating Point (float)
• Void (void)

Question 6

How do you declare and initialize a variable in C++?

Answer 6

Use the syntax scope type identifier = value;
(e.g., global int x = 5;)

Question 7

What is a scope in C++?

Answer 7

A scope defines the region of code where a variable is accessible. Variables in a local scope (like inside a function) are not accessible outside of it.

Question 8

What are the 3 different types of scope?

Answer 8

• Global: Variable is declared outside all functions and is accessible throughout the program, but not from other files
• Local: Variable is only accessible within the function or block where it is declared, only exists during an invocation and ceases to exist at the end of it
• Local Statics: Variable is declared during first invocation and doesn’t cease to exist at the end of it

Question 9

What is the difference between stack and heap memory?

Answer 9

Stack memory is used for local variables and function calls, while heap memory is for dynamic allocation, managed manually

Question 10

What are the roles of new and delete in C++?

Answer 10

• new allocates memory on the heap
• delete deallocates memory to avoid memory leaks

Question 11

What is malloc and how is it used in C++?

Answer 11

• Function in C++ to allocate a block of memory on the heap
• Returns a pointer to the beginning of the block
• Unlike new, malloc does not call constructors and requires explicit casting of the returned pointer to the desired data type
• Memory allocated with malloc should be deallocated using free()

Question 12

What are the 3 elements of a flowchart?

Answer 12

• Activity (rectangular block, e.g. instructions, subprograms, …)
• Decision (diamond, condition (e.g. Boolean expression) is specified)
• Terminal activity (rounded rectangle)

Question 13

What is the structured program theorem?

Answer 13

Flow graphs can compute any computable function by composing the following 3 control structures:
- Sequential execution (execute one subprogram and after that another one)
- Conditional branch, selection (execute one of two subprograms according to the value of a Boolean expression)
- Loop (repeat execution of a subprogram as long as a Boolean expression evaluates to true each time before executing the subprogram)

Question 14

What is a block scope in C++?

Answer 14

• Block scope refers to variables declared within a block of code, enclosed by {}
• These variables are only accessible within that block

Question 15

How does a switch statement work in C++?

Answer 15

• A switch statement evaluates an expression and executes the corresponding case block
• If no cases match, the default block (if provided) is executed

Question 16

What is the purpose of the break statement in a switch case?

Answer 16

break exits the switch statement to prevent “fall-through” to the next case (execution continues until break is encountered)

Question 17

What is a function in C++?

Answer 17

• A function is a block of code designed to perform a specific task
• It can accept inputs (parameters) and return a result

Question 18

How can the parameters given to a function be changed?

Answer 18

If given as a reference (e.g. int& a), the variable can be changed in the function and persists after, not just as local variable

Question 19

What is a const reference?

Answer 19

• The variable data is not copied and given to the function and it is not editable
• Safe and easy
• E.g. void func(const a& data)
• Faster than function call by value

Question 20

What is a function prototype in C++ and why is it used?

Answer 20

• A function prototype declares a function’s return type, name, and parameters before its definition
• It is used to inform the compiler about the function’s existence

Question 21

How do you define a function in C++?

Answer 21

A function is defined with a return type, name, parameter list, and body:
return_type function_name(parameters) { body }

Question 22

What is recursion in C++?

Answer 22

Recursion occurs when a function calls itself to solve a smaller instance of the same problem, often used in algorithms like factorial calculation

Question 23

What is a for loop and when would you use it?

Answer 23

• A for loop is used for iterating a fixed number of times
• It consists of initialization, condition, and increment/decrement expressions

Question 24

How does a while loop differ from a do-while loop in C++?

Answer 24

• while loop checks the condition before executing the loop body
• do-while loop checks the condition after, ensuring the body executes at least once

Question 25

What is a pointer in C++?

Answer 25

• A pointer is a variable that stores the memory address of another variable
• It is declared using the * operator

Question 26

How do you access the value pointed to by a pointer?

Answer 26

Use the dereference operator * to access the value at the memory address stored by the pointer

Question 27

What is a reference in C++?

Answer 27

• A reference is an alias for another variable, declared using the & operator
• It must be initialized when declared

Question 28

What is the difference between ++x and x++ in C++?

Answer 28

• ++x is pre-increment (increments before the value is used)
• x++ is post-increment (increments after the value is used)

Question 29

What are the logical operators in C++?

Answer 29

Logical operators include:
- && (AND)
- || (OR)
- ! (NOT)
used to combine or negate boolean expressions

Question 30

What is the sizeof operator used for in C++?

Answer 30

The sizeof operator returns the size, in bytes, of a data type or object

Question 31

What is a conditional (ternary) operator in C++?

Answer 31

• The conditional operator (?:) is a shorthand for an if-else statement
• It evaluates an expression and returns one of two values depending on the result

Question 32

How do you handle errors in C++ using exceptions?

Answer 32

Use try to wrap the code that might throw an exception, catch to handle exceptions, and throw to generate an exception

Question 33

What is an array in C++?

Answer 33

An array is a collection of elements of the same type, stored in contiguous memory locations, and accessed by index

Question 34

How do you declare an array in C++?

Answer 34

• Use the syntax type array_name[size];
• E.g., int numbers[10];

Question 35

What is function overloading in C++?

Answer 35

• If two functions have the same name, but different parameter types
• Call is only clear sometimes, but if different types are used, type conversion might be needed

Question 36

What is the main function in C++?

Answer 36

• Start of the execution of the program
• Returns 0 (success), error if return otherwise

Question 37

What is a structure in C++?

Answer 37

• Binds together multiple variables in a record
• struct type_name {variables;} object_name1, object_name2;

Question 38

What is the primary idea behind object orientation?

Answer 38

• Organize software as an abstraction of real-world entities
• Objects encapsulate data and methods, and classes provide a blueprint to create multiple objects with similar structure and behavior

Question 39

What is the difference between a class and an object?

Answer 39

• A class is a blueprint or a description of a type of object, defining its properties and behaviors
• An object is an instance of a class, possessing unique identity and the attributes and behaviors defined by its class, several objects can have the same class

Question 40

How are classes represented in UML?

Answer 40

In UML, a class is represented as a rectangle with three compartments:
- The top contains the class name
- The middle lists attributes
- The bottom lists methods