C Programming Interview Questions

Top 10 Essential C Programming Interview Questions

Are you searching for C programming interview questions?  To aid you in your preparation, here is a list of 10 important ones you cannot miss.

The C Programming Language (sometimes called K&R after its authors’ initials) is a computer programming book written by Brian Kernighan and Dennis Ritchie; the latter originally designed and implemented the language as well as co-designed the Unix operating system with which the development of C language was closely intertwined. The book was central to the development and popularization of the C programming language and is still widely read and today. Because the book was co-authored by the original language designer and the first edition of the book served as the de facto standard for the language for many years, the book was regarded by many to be the authoritative reference on C. Source: Wikipedia

1. What are the different features of the C programming language?

Some prominent features offered by C are:

  • C is a structured programming language with fundamental flow control construction.
  • C is a simple and versatile language.
  • C has a rich set of operators.
  • It has only 32 keywords.
  • C is a highly portable programming language.
  • C has several predefined functions.
  • Programs written in C are efficient and fast.
  • C permits all kinds of data conversions and mixed-mode operations.
  • Dynamic memory allocation is possible in C.
  • Extensive varieties of data types such as arrays, pointers, structures, and unions are available in C.
  • C easily manipulates bits, bytes, and addresses.
  • A recursive function is possible in C.
  • The C compiler combines the capability of an assembly-level language with the features of a high-level language.

2. Why is C Programming Language so popular?

C Programming Language is popular because of the following reasons:

  • Programmers can control, allocate, and deallocate memory.
  • Using malloc and calloc functions, memory can be allocated statically, automatically, or dynamically.
  • The C programming language sits close to the operating system
  • The c programming language is used widely in operating systems, network drivers, system utilities, language compilers, and language interpreters.

3. What is a Null pointer in C?

Null is a special reserved value for a pointer in C. Null pointer is different from an uninitialized and dangling pointer.

4. What is a stack in C?

A stack is a data structure that is used to store data in a particular order. Data is stored in stacks using the FILO (First In Last Out) approach. Storing data in a stack known as a PUSH, whereas data retrieval is referred to as a POP. At any particular instance, only the top of the stack is accessible, i.e., in order to retrieve data that is stored inside the stack, you first need to extract the topmost element.

5. How do you write a C program to print “Hello, World”?

int main()
printf(“Hello, World“);
return 0;
// printf() displays the string inside quotation

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6. What are the differences between FOR and WHILE loop?

FOR and WHILE loops are entry controlled loops it means test condition is checked for truth while entering into the loop’s body. The differences between FOR and WHILE loop are:

  • The FOR loop is usually appropriate for loops in which the initialization and increment are single statements and logically related, whereas the WHILE loop keeps the loop control statements together in one place.
  • FOR loop is used in a more compact case as compared to the WHILE loop.

7. What is the difference between the = and == symbols?

The differences between the = and == symbol are:

  • The = symbol is used in mathematical operations, whereas == symbol is a relational operator.
  • = Symbol is used to assign a value to a given variable, whereas == symbol is used to compare two values.

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8. What are the different data types in the C programming language?

The different data types in the C programming language are:

  • Int: Represents an integer.
  • Float: Represents a number with a fraction part
  • Double: Double-precision floating-point value.
  • Char: Represents a single character.
  • Void: Special purpose data type without any value.

9. What is the difference between ++x (pre-increment) and x++ (post-increment)?

The difference between ++x and x++ is:

  • ++X is called prefixed increment and the value of variable X will be incremented before the variable is used.
  • X++ is called postfix increment and the value of variable X will be incremented after the variable is used.

10. What is a sequential access file?

Programs store data into files and then retrieve data from the files. With the sequential access file, the data saved in a sequential pattern. When retrieving data from such files, each data item needs to read one-by-one until the required information is found.

Did these C questions teach you something you weren’t aware of? Is there any concept in the C programming language that is important for interviews? Have you cleared a C-based interview? We’d love to hear from you.

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