Embedded C Interview Questions and Answers

Ques 1. What is embedded C?

Embedded C is a set of extensions to the C programming language specifically designed for embedded systems.

Ques 2. What is a volatile variable in C?

The volatile keyword tells the compiler that a variable's value may change at any time, without any action being taken by the code.

Example:

volatile int sensorValue;

Ques 3. Explain the significance of the 'const' keyword in embedded C.

'const' is used to define constants in C, and in embedded systems, it helps in better code optimization and memory management.

Example:

const int MAX_SIZE = 100;

Ques 4. What is the purpose of the 'volatile' keyword in C?

The 'volatile' keyword is used to indicate that a variable may be changed by external factors, such as an interrupt service routine.

Example:

volatile int flag;

Ques 5. Explain the concept of polling in embedded systems.

Polling involves regularly checking the status of a device or condition within the code, often used for input or communication handling.

Ques 6. What is the role of the 'static' keyword in embedded C?

In embedded C, 'static' can be used to define variables with a fixed memory location or limit the scope of functions and variables.

Example:

static int counter = 0;

Ques 7. What is the purpose of a preprocessor in C?

The preprocessor performs tasks such as macro substitution, file inclusion, and conditional compilation before the actual compilation of the code.

Example:

#define PI 3.14

Ques 8. What is the purpose of the 'inline' keyword in C?

The 'inline' keyword suggests to the compiler that a function should be expanded in-place at the call site, potentially improving performance.

Example:

inline int add(int a, int b) { return a + b; }

Ques 9. What is the purpose of the 'const' pointer in C?

A 'const' pointer points to a constant value, meaning the value it points to cannot be modified through the pointer.

Example:

const int *ptr;

Ques 10. What is the purpose of the 'enum' keyword in C?

The 'enum' keyword is used to define named integer constants, providing a more readable alternative to using raw integer values.

Example:

enum Days { Monday, Tuesday, Wednesday, Thursday, Friday };