C programming skills for a junior embedded software developer to prepare for a job interview

Question 1

What is the purpose of the ‘main’ function in a C program?

Answer 1

The ‘main’ function is the entry point of a C program where execution starts.

Question 2

True or False: In C, a pointer is a variable that stores the memory address of another variable.

Answer 2

True

Question 3

Fill in the blank: The standard library function used to allocate memory dynamically in C is called _____ .

Answer 3

malloc

Question 4

Which of the following is a correct way to declare an integer pointer in C? (a) int p; (b) int *p; (c) pointer int p;

Answer 4

(b) int *p;

Question 5

What does the ‘volatile’ keyword indicate when used in a variable declaration?

Answer 5

It indicates that the variable may be changed by something outside the control of the program, preventing the compiler from optimizing it.

Question 6

What does ‘C’ stand for in the C programming language?

Answer 6

The letter ‘C’ does not stand for anything; it is simply the name of the programming language.

Question 7

True or False: C is a high-level programming language.

Answer 7

True

Question 8

Fill in the blank: The __________ operator is used to access members of a structure in C.

Answer 8

dot

Question 9

What is the purpose of a pointer in C?

Answer 9

A pointer is used to store the address of another variable.

Question 10

Which of the following is a valid variable declaration in C? (a) int 1number; (b) float number1; (c) char @name;

Answer 10

b) float number1;

Question 11

What is the output of the following code: printf(‘%d’, 5 + 3);?

Answer 11

8

Question 12

What does ‘malloc’ function do in C?

Answer 12

It allocates a specified amount of memory during runtime.

Question 13

True or False: C supports function overloading.

Answer 13

False

Question 14

What is the purpose of the ‘return’ statement in a function?

Answer 14

It ends the function and optionally returns a value to the caller.

Question 15

Fill in the blank: The __________ statement is used to create a loop that continues until a specified condition is false.

Answer 15

while

Question 16

What is an array in C?

Answer 16

An array is a collection of variables of the same type stored in contiguous memory locations.

Question 17

What is the correct syntax to declare a function in C?

Answer 17

return_type function_name(parameter_type parameter_name) { /* function body */ }

Question 18

True or False: In C, a string is an array of characters terminated by a null character.

Answer 18

True

Question 19

What is the purpose of the ‘typedef’ keyword in C?

Answer 19

It is used to create an alias for an existing data type.

Question 20

Which of the following is the correct way to comment a single line in C? (a) // comment (b) /* comment */ (c) # comment

Answer 20

a) // comment

Question 21

What is the significance of the ‘main’ function in a C program?

Answer 21

It is the entry point of the program where execution begins.

Question 22

Fill in the blank: The __________ function is used to read input from the user in C.

Answer 22

scanf

Question 23

What does the ‘break’ statement do in a loop?

Answer 23

It terminates the loop and transfers control to the statement following the loop.

Question 24

True or False: In C, all variables must be declared before they are used.

Answer 24

True

Question 25

What is a structure in C?

Answer 25

A structure is a user-defined data type that allows grouping of variables of different types.

Question 26

What is the purpose of the 'sizeof' operator?

Answer 26

It returns the size, in bytes, of a data type or variable.

Question 27

Which of the following is a logical operator in C? (a) && (b) + (c) -

Answer 27

a) &&

Question 28

What is the difference between '==' and '=' in C?

Answer 28

'==' is used for comparison, while '=' is used for assignment.

Question 29

Fill in the blank: The __________ directive is used to include standard input and output functions in a C program.

Answer 29

#include

Question 30

What is the function of the 'continue' statement in a loop?

Answer 30

It skips the current iteration and continues with the next iteration of the loop.

Question 31

True or False: C allows for recursion in functions.

Answer 31

True | https://www.youtube.com/watch?v=kepBmgvWNDw

Question 32

What is a union in C?

Answer 32

A union is a user-defined data type that allows storing different data types in the same memory location.

Question 33

Which keyword is used to define a constant in C?

Answer 33

const

Question 34

What does the 'enum' keyword do in C?

Answer 34

It defines a variable that can hold a set of predefined constants.

Question 35

What is the output of the following code: printf('%d', 10 / 3);?

Answer 35

3

Question 36

What is the purpose of header files in C?

Answer 36

Header files contain declarations of functions and macros to be shared among multiple source files.

Question 37

Fill in the blank: The __________ function is used to free dynamically allocated memory.

Answer 37

free

Question 38

What is the difference between 'struct' and 'class' in C?

Answer 38

'struct' is used in C, while 'class' is used in C++ for object-oriented programming.

Question 39

True or False: C supports multiple inheritance.

Answer 39

False

Question 40

Which of the following is a valid pointer declaration? (a) int *p; (b) int p*; (c) *int p;

Answer 40

a) int *p;

Question 41

What does the 'volatile' keyword indicate in C?

Answer 41

It tells the compiler that the variable can be changed unexpectedly, preventing optimization.

Question 42

What is a segmentation fault?

Answer 42

A segmentation fault is an error that occurs when a program tries to access a memory location that it is not allowed to access.

Question 43

True or False: C allows implicit type conversion.

Answer 43

True

Question 44

What is the purpose of the 'static' keyword in C?

Answer 44

It restricts the visibility of a variable or function to the file in which it is defined.

Question 45

Fill in the blank: The __________ function is used to terminate a program in C.

Answer 45

exit

Question 46

What is the role of the preprocessor in C?

Answer 46

The preprocessor processes directives before compilation, such as including header files and macro definitions.

Question 47

Which of the following is an example of a conditional statement in C? (a) for (b) if (c) switch-case

Answer 47

b) if

Question 48

What does 'bss' stand for in memory segments?

Answer 48

Block Started by Symbol

Question 49

True or False: The 'sizeof' operator can be used with user-defined types.

Answer 49

True

Question 50

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

Answer 50

It exits from the switch-case block after executing a case.

Question 51

Fill in the blank: The __________ operator is used to perform bitwise AND in C.

Answer 51

&

Question 52

What is the difference between '++i' and 'i++'?

Answer 52

'++i' increments 'i' before the value is used, while 'i++' increments 'i' after the value is used.

Question 53

What is a memory leak?

Answer 53

A memory leak occurs when a program allocates memory but fails to release it back to the operating system.

Question 54

True or False: The 'goto' statement is generally recommended for use in C programming.

Answer 54

False

Question 55

What does the 'extern' keyword do?

Answer 55

It declares a variable that is defined in another file or scope.

Question 56

Fill in the blank: The __________ function is used to copy strings in C.

Answer 56

strcpy

Question 57

What is the purpose of the 'assert' macro?

Answer 57

It is used to perform runtime checks and validate assumptions in the code.

Question 58

What does 'volatile' keyword imply about a variable's value?

Answer 58

The value of a volatile variable may change at any time without any action being taken by the code the compiler finds nearby.

Question 59

What is a callback function?

Answer 59

A callback function is a function that is passed as an argument to another function and is invoked at a certain point.

Question 60

True or False: C allows for dynamic memory allocation.

Answer 60

True

Question 61

What is the purpose of the 'sizeof' operator?

Answer 61

It returns the size in bytes of a variable or data type.

Question 62

Fill in the blank: The __________ operator is used to compare two values for inequality.

Answer 62

!=

Question 63

What does the 'continue' statement do in a loop?

Answer 63

It skips the current iteration and proceeds to the next iteration of the loop.

Question 64

What is a dangling pointer?

Answer 64

A dangling pointer is a pointer that does not point to a valid object of the appropriate type.

Question 65

True or False: C is platform-dependent.

Answer 65

True

Question 66

What is the difference between 'struct' and 'typedef struct'?

Answer 66

'struct' defines a structure, while 'typedef struct' creates an alias for a structure type.

Question 67

What is a null pointer?

Answer 67

A null pointer is a pointer that does not point to any valid memory location.

Question 68

Fill in the blank: The __________ function is used to concatenate two strings in C.

Answer 68

strcat

Question 69

What is the purpose of the 'volatile' keyword?

Answer 69

It informs the compiler that the value of a variable may change unexpectedly.

Question 70

What is the use of the 'switch' statement?

Answer 70

The 'switch' statement allows the execution of different parts of code based on the value of a variable.

Question 71

True or False: The C programming language was developed in the 1970s.

Answer 71

True

Question 72

What is the primary purpose of using header files in C?

Answer 72

To declare functions and macros that can be shared across multiple source files.

Question 73

What does 'printf' function do?

Answer 73

It outputs formatted text to the standard output (usually the console).

Question 74

Fill in the blank: The __________ operator is used for bitwise OR in C.

Answer 74

|

Question 75

What is a function prototype?

Answer 75

A function prototype is a declaration of a function that specifies its name, return type, and parameters.

Question 76

True or False: The 'main' function can return a value other than 0.

Answer 76

True

Question 77

How do you prevent memory leaks in C?

Answer 77

Always free() memory allocated with malloc() or calloc() Avoid unnecessary dynamic allocation in embedded systems Use tools like Valgrind or custom debug allocators Track allocations with logs or counters Initialize pointers to NULL and check before freeing Avoid memory allocation in ISRs or frequently called functions