Introduction

At Bell Labs, Dennis Ritchie developed the C programming language between 1971 and 1973. C is a mid-level structured-oriented and general-purpose programming language which is considered one of the oldest and most popular programming languages. It has a wide range of applications, from language compilers and operating systems to assemblers, network drivers, text editors, print spoolers, modern applications, language interpreters, databases and utilities.

C Programming language is often perceived as complex but it is still an invaluable tool for enhancing your programming capabilities. Depending on experience level and individual proficiency with coding, questions related to C can be divided into two categories:

1. Freshers

2. Experienced coders.

This article “C Programming Questions” aims to provide a comprehensive resource for those seeking to prepare for C programming questions for interviews, both for fresher and more experienced levels. To begin, we will focus on the types of questions typically asked of those with limited experience in the field. We have gathered a list of the most commonly asked C Programming questions, as well as detailed answers that can help you showcase your knowledge and understanding of the language. Whether you are an entry level programmer or an experienced professional, these questions and their answers should be helpful in preparing you for success in your next C programming interview. Let’s see in this C programming question, what can the interviewer ask about?

1. Why is C called a mid-level programming language?

In this C programming question, Interviewer may asked you about- C is a versatile programming language which is why it is commonly referred to as a middle-level language – it has the ability to incorporate both low and high-level features. This means it can be used to write programs that are converted into assembly code as well as being machine-independent, providing the programmer with the flexibility of pointer arithmetic (low-level) and ease of use (high-level). C is often utilized for writing operating systems and menu-driven consumer billing systems due to its impressive combination of features.

Let’s delve a little deeper and uncover a few more C programming questions.

2. What are basic data types supported in the C Programming Language?

In this C programming question, the interviewer may inquire about the each variable which has an associated data type that dictates how much memory it requires, the range of values it can store, and the operations that can be performed on it. Data types are divided into four main categories: integer, character, floating-point (or real), and double-precision floating-point. In C data types are broadly classified into 4 categories:

• Primitive data types:

Primitive data types can be further classified into two main categories: integer and floating. Integer data types are used to represent a whole number, while floating data types are used to represent numbers with decimal points.

• Void Types: 

Void data types, which fall under the umbrella of primitive data types, provide no result to their caller and have no associated value. In other words, a void data type is essentially used to signify that nothing should be returned from a function – it is a placeholder for an empty value.

• User Defined data types:

These data types are defined by the user to make the program more easily understandable. By assigning meaningful names to values, data variables, and operations within a program, it can be read like a sentence instead of a jumble of numbers and symbols.

• Derived data types:

There are several kinds of data types that can be derived from primitive or built-in data types. These derived data types can be classified into two broad categories – composite and abstract. Composite data types are composed of multiple components, such as arrays, records, and objects.

Let’s take a plunge into the depths of C programming questions and reveal a more mysteries.

3. What are tokens in C?

Tokens are the smallest individual pieces of code that a compiler can recognize and interpret within a program. In the C programming questions languages, there are several types of tokens, including identifiers, operators, punctuation symbols, and keywords.

• Keywords:

These keywords are essential for programming in C, as they provide the foundation for more complex functions and operations.

• Identifiers:

Identifiers are user-defined names that can be composed of an unlimited number of either digits or letters, as long as the first character is a letter or an underscore (_). It is important to note that identifiers must not match any of the reserved keywords within the C programming language.

• Constants:

Constants are particularly useful when coding in languages such as C and C++, where values often need to remain consistent and unchanging in order to ensure the desired function of the program.

• Strings:

Strings in C are an array of characters that terminate with a special character known as the null character (‘’). This null character indicates the end of the string, and is essential for the string to be properly identified and interpreted by the compiler.

• Special Symbols:

C programming language utilizes a variety of special symbols that have specific meanings and cannot be used for any other purpose. These symbols include the pound sign (#), curly brackets ({}), parentheses (()), comma (,), asterisk (*), semicolon (;) and square brackets ([]).

• Operators:

The C Programming language utilizes a range of symbols known as operators. These operators are divided into three distinct categories: Unary, Binary, and Ternary. Depending on the type of operator used, different actions can be triggered when they are applied.

Let’s explore language C further by asking more C programming questions.

4. What is the difference between malloc() and calloc() in the C programming language?

The calloc() and malloc() library functions are used to allocate dynamic memory in the C Programming language. Dynamic memory is essentially memory that is allocated during the runtime of the program from the heap segment – meaning it can be used without needing to be declared ahead of time. In order for access to these library functions, you must include the “stdlib.h” header file, which facilitates dynamic memory allocation within the program.

Parameter	Malloc()	Calloc()
Definition	This function provides the capabil ity to create a single contiguous block of memory, with a specified size that cannot be altered. It is especially useful for allocating large amounts of memory at once, as it avoids having to create multiple smaller blocks. Memory allocated in this way can be used to store and manipulate data such as arrays of numbers or characters.	This function is extremely useful in programming, as it allows a single variable to be assigned multiple blocks of memory. This means that a program can store more complex data types such as arrays or linked lists, which would otherwise require many individual variables to store. By using this function, programs can become more efficient and streamlined, saving both time and memory.
Number of arguments	It only takes one argument to make a difference; this single assertion can be the deciding factor in any debate or discussion. It could be the one thing that helps convince others of your point of view, swaying them to your opinion. This concept is why it’s important to make sure that any argument you present is well-thought out and convincing, as it could be the deciding point in the whole conversation.	This function requires two arguments to be passed in order to execute properly, each argument providing specific information that is essential for the function to work correctly.
Speed	The malloc() function is known to be faster than the calloc() function when it comes to memory allocation. This is because the malloc() function only requires a single pass through the memory, whereas calloc() requires two passes in order to properly initialize each element of the allocated memory block. Furthermore, malloc() does not require the additional step of setting all the bytes in the allocated block to 0, as calloc() does. This makes malloc() more effective and efficient when dealing with larger blocks of memory, as it can save time by eliminating one or more steps in the process.	Although calloc() and malloc() are both C library functions used to request memory allocations, calloc() is typically slower than malloc(). This is because calloc()’s primary purpose is to initialize the allocated memory by setting all bytes in allocated memory blocks to zero, while malloc() only allocates the requested amount of memory. While this extra step of allocating and setting the memory to 0 may be necessary in some cases, it does slow down the process compared to malloc(), which simply allocates requested memory.
Efficiency	When making decisions, time efficiency must be considered.	This method takes a long time to finish tasks, making it hard to meet deadlines.
Usage	Memory allocation is the act of assigning a portion of a computer system’s memory to store data or instructions.	Contiguous memory allocation is a data storage technique in which related elements are stored consecutively in memory.

Let’s go deeper and ask more C programming questions.

5. What do you mean by dangling pointers and how are dangling pointers different from memory leaks in C programming?

What knowledge do you have about C programming questions? This question from the interviewer can provide insight into a dangling pointer in C Programming is a pointer that points to a memory block that has been deallocated, meaning the variable it was pointing to has been deleted and yet the pointer still points to the same memory location. This can lead to a memory leak, which occurs when memory is allocated with the help of library functions malloc() or calloc(), but then forgotten about and not freed with the free() library function. As a result, an undefined amount of RAM is taken up by the program, making it unavailable for other applications which can cause our program to crash.

Now, let us investigate further and uncover additional C programming questions.

6. What is recursion in C?

Recursion is the process of making a function call itself directly or indirectly in order to solve a particular problem. This process involves breaking down the original problem into smaller subproblems and then calling a copy of the same function to solve them. This method of solving problems helps to reduce code complexity and length, as well as make it easier to comprehend. The recursive function relies on a Last In First Out (LIFO) structure like a stack, where each recursive call requires additional space in the stack memory. This way, multiple calls can be stored until they are ready to be executed one by one in reverse order.

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

Local variables are declared within the confines of a block or function, and cannot be accessed outside of this context. Conversely, global variables are declared outside of a block or function, making them available throughout the program, regardless of their location in the code. This allows global variables to be used for values that need to be shared between different parts of the codebase, such as configuration settings or user data.

8. What are pointers and their uses? 

The interviewer may pose the following C programming questions: Pointers are like the GPS for your computer, pinpointing exact locations in memory. With a pointer, you can direct your program to a specific variable or memory location. This allows for efficient use of resources, helping you save both memory space and time! And that’s not all – pointers can also be used to refer to other pointer functions are-

• To pass arguments by reference
• For accessing array elements
• To return multiple values
• Dynamic memory allocation
• To implement data structures
• To do system-level programming where memory addresses are useful

9. What is the difference between type casting and type conversion?

You can noticed several difference between type casting and type conversion in this C programming questions blog-

10. What are header files and their uses?

Ready to test your C programming mettle? See how you fare with this C programming questions: C language has numerous libraries with predefined functions to simplify programming. Header files, which must have a “.h” extension, contain function definitions, data type definitions, and macros. These can be imported into a program using the preprocessor directive “#include”. There are two types of header files: user-defined and pre-existing. For example, if code needs to take input from the user and print output, “#include<stdio.h>” must be included in the program. This header file contains functions such as scanf() and printf() for taking input from the user and printing content.

Conclusion

In conclusion, we have seen that C programming is a versatile and powerful language for developing programs. It provides powerful data types and operators, as well as a wide variety of functions for managing memory and files. Additionally, the syntax can be simple to learn or quite complex depending on the user’s needs. With the right tools and techniques, it can easily help create robust applications with efficient code execution while also providing portability across different platforms. All in all, C programming is an excellent choice for anyone looking to write their own software projects.

Frequently Asked Questions