C Programming Interview Questions Answers

In this blog post, we will discuss C programming interview questions and answers, here we have provided you with top 40 questions and answers related to C programming language, which are asked in interview. If you go for an interview in any IT sector company, then all these questions are definitely asked. That’s why we have prepared top 40 questions and answers for you on this blog related C Programming Language. (C Interview Questions and Answers).

Top C Programming Interview Questions & Answers.

Ques 1. What is C programming language?

Answer: C is a high-level programming language that was developed by Dennis Ritchie in the early 1970s. It is a general-purpose language that is widely used for system programming, embedded systems, and application programming.

 

Ques 2. What is a pointer in C?

Answer: A pointer is a variable that stores the memory address of another variable. It allows you to access and manipulate the value stored in the memory location of that variable.

 

Ques 3. What is the difference between an array and a pointer?

Answer: An array is a collection of elements of the same data type that are stored in contiguous memory locations, while a pointer is a variable that stores the memory address of another variable.

 

Ques 4. What is the difference between ++i and i++?

Answer: ++i is the pre-increment operator, which increments the value of i before using it in the expression, while i++ is the post-increment operator, which increments the value of i after using it in the expression.

 

Ques 5. What is the difference between a structure and a union in C?

Answer: A structure is a collection of variables of different data types that are stored in contiguous memory locations, while a union is a special type of structure in which all the variables share the same memory location.

 

Ques 6. What is a function in C?

Answer: A function is a block of code that performs a specific task. It is designed to be reusable and can be called from other parts of the program.

 

Ques 7. What is the difference between a call by value and call by reference in C?

Answer: In call by value, a copy of the value of the argument is passed to the function, while in call by reference, the address of the argument is passed to the function, and the function can modify the value of the argument directly.

 

Ques 8. What is the size of int, float, double, and char data types in C?

Answer: The size of int is 4 bytes, float is 4 bytes, double is 8 bytes, and char is 1 byte.

 

Ques 9. What is the difference between global and local variables in C?

Answer: A global variable is a variable that is declared outside of any function, and it can be accessed from any part of the program. A local variable is a variable that is declared inside a function, and it can only be accessed within that function.

 

Ques 10. What is the use of #define in C?

Answer: #define is a preprocessor directive that is used to define constants or macros. It is used to simplify code and make it more readable.

 

Ques 11. What is a NULL pointer in C?

Answer: A NULL pointer is a pointer that points to nothing. It is used to indicate that a pointer does not point to a valid memory location.

 

Ques 12. What is the difference between malloc and calloc in C?

Answer: malloc is used to allocate a block of memory of a specified size, while calloc is used to allocate a block of memory and initialize it to zero.

 

Ques 13. What is the use of typedef in C?

Answer: typedef is used to create an alias for a data type. It is often used to simplify complex data types or to create more readable code.

 

Ques 14. What is a static variable in C?

Answer: A static variable is a variable that retains its value between function calls. It is only initialized once, and its value is preserved until the end of the program.

 

Ques 15. What is the difference between a while loop and a do-while loop in C?

Answer: In a while loop, the condition is tested at the beginning of each iteration, while in a do-while loop, the condition is tested at the end of each iteration.

Ques 16. What is the difference between signed and unsigned data types in C?

Answer: A signed data type can represent both positive and negative numbers, while an unsigned data type can only represent positive numbers.

 

Ques 17. What is a bit field in C?

Answer: A bit field is a data structure that is used to pack multiple variables of smaller size into a single memory location. It is often used to save memory and optimize performance.

 

Ques 18. What is the difference between a header file and a source file in C?

Answer: A header file contains declarations of functions, variables, and data types, while a source file contains the actual implementation of the functions.

 

Ques 19. What is a macro in C?

Answer: A macro is a preprocessor directive that is used to define a code snippet that can be reused multiple times in the program. It is often used to simplify code and make it more readable.

 

Ques 20. What is a switch statement in C?

Answer: A switch statement is a control structure that allows you to test the value of a variable and execute different blocks of code based on the value.

C Programming Interview Questions Answers

Ques 21. What is a bitwise operator in C?

Answer: A bitwise operator is an operator that performs operations on individual bits of a number. It is often used in low-level programming and for bitwise manipulation of data.

 

Ques 22. What is the difference between a break statement and a continue statement in C?

Answer: A break statement is used to terminate a loop or a switch statement, while a continue statement is used to skip the current iteration of a loop and move on to the next iteration.

 

Ques 23. What is a const keyword in C?

Answer: The const keyword is used to declare a variable as read-only. Once a variable is declared as const, its value cannot be changed.

 

Ques 24. What is a typedef struct in C?

Answer: A typedef struct is used to create a user-defined data type that combines multiple variables of different data types into a single entity.

 

Ques 25. What is a header guard in C?

Answer: A header guard is a preprocessor directive that is used to prevent multiple inclusions of the same header file in the program. It is often used to avoid duplicate declarations and definitions.

 

Ques 26. What is the difference between stack and heap memory in C?

Answer: Stack memory is used to store local variables and function parameters, while heap memory is used to allocate memory dynamically using functions like malloc and calloc.

 

Ques 27. What is a file pointer in C?

Answer: A file pointer is a pointer that points to a file stream. It is used to read from or write to a file.

 

Ques 28. What is the difference between fopen and fclose in C?

Answer: fopen is used to open a file, while fclose is used to close a file after it has been opened.

 

Ques 29. What is the difference between fread and fwrite in C?

Answer: fread is used to read data from a file, while fwrite is used to write data to a file.

Ques 30. What is a command-line argument in C?

Answer: A command-line argument is an argument that is passed to the program when it is run from the command line. It is often used to pass input or configuration parameters to the program.

 

Ques 31. What is the difference between an if statement and a switch statement in C?

Answer: An if statement is used to test a single condition, while a switch statement is used to test multiple conditions based on the value of a variable.

 

Ques 32. What is a function pointer in C?

Answer: A function pointer is a pointer that points to a function. It can be used to pass functions as arguments to other functions, or to store and retrieve functions from data structures.

 

Ques 33. What is a recursive function in C?

Answer: A recursive function is a function that calls itself repeatedly until a certain condition is met. It is often used to solve problems that can be broken down into smaller subproblems.

 

Ques 34. What is the difference between pass by value and pass by reference in C?

Answer: Pass by value means that a copy of the variable is passed to the function, while pass by reference means that the address of the variable is passed to the function. Pass by value is used when the function only needs to read the variable, while pass by reference is used when the function needs to modify the variable.

 

Ques 35. What is the difference between a static variable and an automatic variable in C?

Answer: A static variable is a variable that retains its value between function calls, while an automatic variable is a variable that is created and destroyed each time the function is called.

 

Ques 36. What is a pointer in C?

Answer: A pointer is a variable that stores the memory address of another variable. It is often used to manipulate data structures and to pass data between functions.

 

Ques 37. What is a NULL pointer in C?

Answer: A NULL pointer is a pointer that points to nothing. It is often used to represent an invalid or uninitialized pointer.

 

Ques 38. What is a linked list in C?

Answer: A linked list is a data structure that consists of a sequence of nodes, where each node contains a data field and a pointer to the next node in the list.

 

Ques 39. What is a stack in C?

Answer: A stack is a data structure that stores data in a last-in, first-out (LIFO) order. It is often used for function calls, expression evaluation, and other operations that require a temporary storage of data.

 

Ques 40. What is a queue in C?

Answer: A queue is a data structure that stores data in a first-in, first-out (FIFO) order. It is often used for buffering and scheduling operations that require a sequential processing of data.

Conclusion

So, you learned here Top 40 C Programming Interview Questions with Answers, all these questions are very important if you are from IT sector. I hope you have understood all questions and answers very well and if you have any doubt, regarding it then you can ask in the comment section.

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