C Programming Test Questions and Answers

C Programming Test Questions and Answers – Coding Aptitude Test

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Posted by Aarna Tiwari Aug 23, 2023

Programming languages are crucial in determining an individual’s professional path in the ever-changing field of technology, especially for college students and recent graduates. C programming stands out among these languages as a fundamental language that serves as the basis for many contemporary programming languages. C programming is an essential skill that may significantly improve your job search in the computer industry due to its historical relevance, adaptability, and extensive application.

This article explores a variety of C programming test questions and answers, emphasizing the value of these questions in job interviews and enticing readers to take part in coding and programming competitions on the Firstnaukri website.

What is C Programming Language?

Dennis Ritchie created the C programming language at Bell Labs in the early 1970s, and it is regarded as one of the most significant and durable computer languages. Numerous programs, operating systems, and software tools have been made possible thanks to their simplicity, effectiveness, and portability.

Having a static type system and enabling lexical variable scope, recursion, and structured programming, C is a general-purpose procedural programming language. Applications previously written in assembly language have found enduring use in C because they offer structures by design that transfer effectively to conventional machine instructions.

C Programming Test Questions and Answers PDF

System programming, embedded systems, and high-performance applications all benefit from C programming’s close-to-hardware capabilities.

C Programming Test Questions and Answers

If you are interested in learning how to program, C is a great language to start with. It is a powerful and versatile language that can be used to create a wide variety of software.

Check Out these most common C programming aptitude questions and answers.

Declarations and Initializations Questions

What is the difference between a declaration and an initialization in C programming?

A declaration in C programming is the process of telling the compiler that a variable, function, or data structure exists and what type it is. Without creating a memory for the item, it tells the compiler its name and type.

An initialization, on the other hand, entails giving a defined variable a starting value. The variable is initialized by allocating memory for it and setting its value. While initializations offer starting values for variables, declarations are necessary for the compiler to comprehend the structure of the program.

What are the different types of variable initialization in C?

There are two types of variable initialization in C:

  • Static initialization: Static initialization is the process of assigning a value to a variable in its declaration statement.
  • Dynamic initialization: Dynamic initialization is the process of assigning a value to a variable at runtime.

Static initialization is typically used for variables that need to have a value assigned to them before the program starts running. Dynamic initialization is typically used for variables that need to have a value assigned to them at runtime, based on user input or other factors.

Explain the difference between automatic, static, and dynamic initialization of variables in C programming.

In C programming, variables can be initialized in different ways:

  • Automatic Initialization: Also known as default initialization, automatic initialization initializes variables with a default value, which is usually 0 for numeric types and NULL for pointers. Automatic variables declared within functions are automatically initialized to these default values.
  • Static Initialization: Static variables, which are declared using the static keyword, are initialized only once before the program starts execution. If not explicitly initialized, they are set to 0 or NULL, like automatic variables. If explicitly initialized, they retain that value throughout the program’s lifetime.
  • Dynamic Initialization: Dynamic initialization involves initializing variables at runtime using functions or values computed during program execution. This can include user input, calculations, or reading from files. Dynamic initialization allows for flexibility in assigning values based on runtime conditions.

Control Instructions – C Programming Test

What are control instructions in C?

Control instructions in C are programming constructs that are used to control the flow of execution in a program. They allow the programmer to make decisions, repeat code, and jump to different parts of the program.

What are the different types of control instructions in C?

There are three types of control instructions in C:

  • Selection instructions: Selection instructions are used to make decisions based on the value of a condition. The most common selection instructions in C are the if statement, the else statement, and the switch statement.
  • Iteration instructions: Iteration instructions are used to repeat a block of code until a certain condition is met. The most common iteration instructions in C are the while loop, the for loop, and the do-while loop.
  • Jump instructions: Jump instructions are used to transfer control to a different part of the program. The most common jump instructions in C are the goto statement and the break statement.

What is the purpose of the “if” statement in C programming, and how is it structured?

In C programming, the “if” statement is used to execute code blocks conditionally. It enables a program to decide if a particular condition is true or untrue in order to take action. The “if” statement is composed as follows:

if (condition) {

// Code to be executed if the condition is true


If the condition inside the parentheses is evaluated as true, the code block enclosed in curly braces is executed. If the condition is false, the code block is skipped.

Expressions Test Questions

What is an expression in C?

An expression in C is a combination of variables, operators, and constants that evaluates to a single value. Expressions can be used to perform arithmetic operations, logical operations, and relational operations.

What is the difference between an expression and a statement in C programming?

In C programming, both expressions and statements play crucial roles, but they have distinct meanings:

  • Expression: When evaluated, an expression is a grouping of variables, operators, constants, and function calls that result in a value. Expressions can be straightforward, such as x + y, or complicated, including a number of subexpressions. Additionally, they may consist of logical, mathematical, and bitwise processes.
  • Statement:A statement is a full instruction that causes a certain program action to be done. Variable declarations, assignments, function calls, control flow structures (if, switch, loops), and more can all be found in statements. Statements, unlike expressions, are evaluated but do not result in a value.


What is a function in C?

A function in C is a block of code that is used to perform a specific task. Functions can be called from anywhere in the program, and they can be used to simplify code and make it more reusable. The different parts of a function in C are

  • The function name: The function name is used to call the function.
  • The function parameters: The function parameters are the values that are passed to the function when it is called.
  • The function body: The function body is the block of code that is executed when the function is called.
  • The function return value: The function return value is the value that is returned by the function when it finishes executing.

What is a function prototype in C programming, and why is it important?

Before a function is defined or called, the name, return type, and parameter types can be communicated to the compiler using a function prototype, sometimes referred to as a function declaration. It acts as the function’s signature’s first description.

The compiler will be able to do type-checking using this information, guaranteeing that the proper functions are called with the appropriate amount and kinds of arguments. Even if the actual function description is included later in the code, it still allows the compiler to produce suitable code for function calls.


What is a string in C?

A string in C is a sequence of characters terminated by a null character ‘\0’. Strings are stored as arrays of characters, and they can be manipulated using a variety of string functions.

How are strings represented in C programming, and what is the significance of the null-terminator?

Strings are represented as character arrays in C programming. The null-terminator (‘0’) is the last character and each character in the array maps to a character in the string. The string’s end is indicated by the null-terminator, a special character having a value of 0. It is crucial because C lacks a built-in data type for strings, therefore functions that work with strings depend on the null-terminator to determine the string’s end.

Input / Output

What are the different types of input/output in C programming?

There are two types of input/output in C:

  • Standard input/output: Standard input is the keyboard, and standard output is the screen. These are the default input and output devices for C programs.
  • File input/output: File input is reading data from a file, and file output is writing data to a file. Files can be used to store data that does not need to be kept in memory, such as large amounts of data or data that needs to be preserved for future use.

What are the different input/output functions in C?

There are many input/output functions in C, but some of the most common ones are:

  • scanf(): The scanf() function reads formatted data from the standard input.
  • printf(): The printf() function writes formatted data to the standard output.
  • fopen(): The fopen() function opens a file for reading or writing.
  • fread(): The fread() function reads data from a file.
  • fwrite(): The fwrite() function writes data to a file.

Command Line Arguments

What are command line arguments in C?

Values provided to a C program during execution are known as command line arguments. Arguments sent on the command line are frequently used to modify a program’s behavior. For instance, you may define an output format or a program’s input file using command line parameters.

How can you pass command line arguments to a C program, and what is the significance of the argc and argv parameters in the main function?

Command line arguments can be passed to a C program when it is executed from the terminal. The argc (argument count) and argv (argument vector) parameters in the main function are used to access these arguments. 

  • argc: It is an integer that represents the number of command line arguments passed to the program, including the program name itself.
  • argv: It is an array of character pointers (char*) that holds the actual command line argument strings. argv[0] is the program name, and the subsequent elements contain the provided arguments.

Library Functions

What are library functions in C?

In C, pre-written functions that are kept in a library are referred to as library functions. Programs written in C can connect to libraries to offer more functionality. The majority of the time, input/output, text manipulation, and mathematical calculations are performed using library functions.

What are library functions in C programming, and how do they differ from user-defined functions?

In C programming, library functions are pre-written routines that are a part of the general C library or additional specialized libraries. They offer a variety of functionalities, including input/output operations, string manipulation, computations, memory management, and more. Developers can use library functions without having to write new code because they have already been developed and optimized. On the other hand, user-defined functions are ones that the programmer has designed to carry out certain duties. They enable the program’s code to be modular and reused.

The main distinction is that, whereas user-defined functions are generated by programmers to provide customized functionality for a particular program, library functions are created by pre-existing libraries and may only be utilized inside a single program.

What is the Coding Aptitude Test?

An assessment of a candidate’s coding aptitude measures how quickly they can solve algorithmic and coding issues. These aptitude tests are intended to evaluate your coding expertise, logical thinking, and problem-solving skills. 

Technical interviews frequently include coding aptitude tests, particularly for software development positions.


C programming is a talent that has stood the test of time and is still in high demand in the computer sector. Learning the foundations of C programming gives you access to a variety of employment options and develops problem-solving skills that are essential for technical interviews. 

College students and recent graduates have a great opportunity to demonstrate their coding skills through competitions on platforms like Firstnaukri. These competitions frequently include C programming tasks that put your technical know-how to the test while also exposing you to actual problem-solving situations. Participating in Firstnaukri contests might provide you an advantage during job interviews since it shows that you are dedicated to lifelong learning and self-improvement.

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