C Online Test
TestDome skill assessments are used by more than 5,000 companies and 450,000 individual test takers.
Jobseekers: Get a Certificate
Take a Practice TestCompanies: Try First, Pay Later
Sign Up To Use This TestThe C online test assesses candidates' knowledge of programming in the C language.
It's an ideal test for pre-employment screening. A good C developer needs to be able not only to solve problems using C but also understand the implications of low level optimizations.
This online test requires candidates to solve coding problems in C.
Recommended Job Roles
Back-End Developer
C Developer
Sample Candidate Report
Sample Free Questions
Quadratic Equation
10min
-
Easy
-
CODE
C
Arithmetic
Public
New
C
C is a general-purpose, imperative computer programming language, that supports structured programming, lexical variable scope and recursion. Having a basic familiarity with the programming language used on the job is a prerequisite for quickly getting up to speed.
Arithmetic
Arithmetic is a fundamental branch of mathematics. An understanding of arithmetic concepts, and their application, is important for every candidate.
Public
Public questions (free account) are common interview questions. They are great for practicing, or if you want to filter candidates using the classic problems.
New
This is a new addition to our question library.
Implement the function find_roots to find the roots of the quadratic equation: ax2 + bx + c = 0. If the equation has only one solution, the function should return that solution as both roots. The equation will always have at least one solution.
The roots of the quadratic equation can be found with the following formula: 
For example, the roots of the equation 2x2 + 10x + 8 = 0 are -1 and -4.
Watched Videos
10min
-
Easy
-
CODE
C
Arrays
Pointers
Public
C
C is a general-purpose, imperative computer programming language, that supports structured programming, lexical variable scope and recursion. Having a basic familiarity with the programming language used on the job is a prerequisite for quickly getting up to speed.
Arrays
An array is a container of a fixed number of objects of a similar type. It is a fundamental component of most programming languages.
Pointers
A pointer references a location in memory, and obtaining the value stored at that location is known as dereferencing the pointer. Using pointers is something that all C and C++ developers should know.
Public
Public questions (free account) are common interview questions. They are great for practicing, or if you want to filter candidates using the classic problems.
Implement the count_views function. It accepts an array of pointers to the Viewer struct, the size of the array, and the character array with the video name. It should return the number of Viewers who have watched a Video with the name video_name.
For example,
Video videos[] = { {.name = "Soccer", .unique_views = 500},
{.name = "Basketball", .unique_views = 1000} };
Viewer viewer = {.username = "Dave", .watched_videos = videos,
.watched_videos_size = 2};
Viewer *viewers[] = { &viewer };
calling count_views(viewers, 1, "Soccer") should return 1.
Words
10min
-
Easy
Easy
-
CODE
C
Algorithmic thinking
Sorting
Public
C
C is a general-purpose, imperative computer programming language, that supports structured programming, lexical variable scope and recursion. Having a basic familiarity with the programming language used on the job is a prerequisite for quickly getting up to speed.
Algorithmic thinking
When designing and/or analyzing an algorithm or data structure, it is important to consider the performance and structure of an implementation. Algorithmic thinking is one of the key traits of a good programmer, especially one working on complex or performance-critical code.
Sorting
Every programmer should be familiar with data-sorting methods, as sorting is very common in data-analysis processes.
Public
Public questions (free account) are common interview questions. They are great for practicing, or if you want to filter candidates using the classic problems.
Implement function sort_words that sorts an array of words that contain lowercase characters from english alphabet, in descending order, and is efficient with respect to time used.
For example, the array { "cherry", "orange", "apple" } should, after sorting, become { "orange", "cherry", "apple" }.
Premium Questions
The premium question library contains our unique, hand-crafted questions. We offer a refund if you find any of them answered online.
Questions
Allocate String, Copy Bit, Max Sum, Shipping, Init Range, Read Write Execute, Segment, Square, Tiles, Username, Internal Nodes, Battery, Increment, Strings Pointer, Count Letters, Descriptor, Run in Parallel, IncrementSkills
CC
C is a general-purpose, imperative computer programming language, that supports structured programming, lexical variable scope and recursion. Having a basic familiarity with the programming language used on the job is a prerequisite for quickly getting up to speed.
Memory management
Memory management allows programs to request memory dynamically from the operating system, and free it for reuse when no longer needed. Many modern programming languages automate this process; however, it should still be an important consideration when implementing an application.
Bit manipulation
Low-level programming tasks, such as data compression, error detection and device control, often require manipulation of the bits that make up the data, which is an important skill for any programmer working on low-level data processing.
Algorithmic thinking
When designing and/or analyzing an algorithm or data structure, it is important to consider the performance and structure of an implementation. Algorithmic thinking is one of the key traits of a good programmer, especially one working on complex or performance-critical code.
Arithmetic
Arithmetic is a fundamental branch of mathematics. An understanding of arithmetic concepts, and their application, is important for every candidate.
Strings
The string data structure is used to represent text. It is one of the most commonly used data structures. Therefore, every programmer should be skilled at string manipulation.
Pointers
A pointer references a location in memory, and obtaining the value stored at that location is known as dereferencing the pointer. Using pointers is something that all C and C++ developers should know.
2D array
A two-dimensional array is an array of arrays, organized as a matrix. It is often used when the number of rows and columns are already known and don't change over time.
Pass by reference
The call by reference method of passing arguments to a function copies the reference of an argument into the formal parameter. Inside the function, the reference is used to access the actual argument used in the call. This means that changes made to the parameter affect the passed argument. This is one of two possible ways for passing an argument to a function so it should be known to any developer.
Regex
A regular expression (regex) is a special text string for describing a search pattern. It is a common way for extracting data from text.
Arrays
An array is a container of a fixed number of objects of a similar type. It is a fundamental component of most programming languages.
Tree
A tree is a hierarchical structure defined recursively starting with the root node, where each node is a data structure consisting of a value, together with a list of references to other nodes (the "children"). A lot of problems can be solved efficiently with trees, which makes them important for developers.
Language
A programmer should use a language as a tool, always taking advantage of language-specific data types and built-in functions.
Pointer to pointer
Pointer to pointer is when one pointer is used to store the address of another pointer. It can be used as an array of arrays or to change the value of the pointer passed as an argument to the function.
Higher order function
A higher order function is a function that takes another function as an argument, or returns another function. Developers often use them for writing reusable code.
Multithreading
Multi-threading allows a process to make more efficient use of modern hardware by allowing code to execute asynchronously. It can drastically improve the performance of any app; however, it can be tricky to get right, making this an important topic for any programmer.
Score Distribution
# of candidates
| 0-33% | |
|---|---|
| 34-66% | |
| 67-100% |
Score