C is a general-purpose and high-level programming language. It is widely used for developing operating systems, embedded systems, and other applications that require low-level access to a computer's hardware. C is known for its efficiency, portability, and flexibility.


Features of Online C Compiler

  • It can be accessed through any web browser
  • Easy to use interface and supports various libraries.
  • The syntax highlighting feature colours the elements of the code to increase readability.
  • Compiler’s Autocompletion feature accelerates coding by predicting already defined variables/functions and completing code.

Syntax Help

In C programming language, syntax helps to define the structure of a C program and how different elements of the language, such as variables, functions, and control structures, can be used to create a working C program.

1. If-Else Statement:

In C programming language, the if-else statement is a control flow statement. It checks whether a certain condition is true or false. The syntax of the if-else statement is mentioned below:

if (condition1) {
    // code will be executed if condition1 is true
else {
    // code will be executed if condition1 is false

2. Switch Statement:

In C programming language, the switch statement is a control flow statement it allows you to perform different actions based on the value of a variable or expression. The syntax of the switch statement is mentioned below:

switch (expression) {
    case value1:
        // code will be executed if the expression is equal to value1
    case value2:
        // code will be executed if the expression is equal to value2
        // code to be executed if the expression does not match any of the cases

3. For Loop:

In C programming language, the for loop is a control flow statement it allows you to execute a block of code a specified number of times. The syntax of the for loop is mentioned below:

for (initialization; condition; increment) {
    // code to be executed

4. While Loop:

In C programming language, the while loop is a control flow statement it allows you to execute a block of code repeatedly until a certain condition is true. The syntax of the while loop is mentioned below:

while (condition) {
    // code to be executed

5. Do-While Loop:

In C programming language, the do-while loop is a control flow statement, the code block inside the loop is executed at least once before the condition is checked. The syntax of the do-while loop is mentioned below:

do {
    // code to be executed
} while (condition);



In C programming language, a string is a sequence of characters stored in memory. A string can be used to store texts, for example, words, sentences, or paragraphs. Strings are represented by arrays of characters, in which the last character is a special character called the null character ('\0') which shows the end of the string.

Syntax of strings

Here's an example of how to declare a string in C programming language:

char myStr[6] = "Hello Ninjas";


In C programming language, an array is a collection of elements of the same data types, stored in a contiguous block of memory. Each element in the array can be accessed by its index, which is an integer value that corresponds to the element's position in the array.


There are various types of arrays in C such as 

  1. One-dimensional arrays: It is a linear collection of elements, in which each element can be accessed through a single index.
  2. Jagged arrays: It is an array of arrays with different lengths, in which each element of the main array is an array itself. 
  3. Multi-dimensional arrays: It is an array of arrays, in which each element of the main array is an array itself.
  4. Character arrays: It is a one-dimensional array of characters, used to store sequences of characters as strings.


The syntax of declaring an array in C programming language is

data_type array_name[array_size];

For example,

int myArr[5];


Functions in C

In C programming language, a function is a block of code that performs a specific task. Functions can take input in the form of parameters and can return output in the form of a return value. There are two types of functions available in C language, user-defined, and standard library functions.

How to declare Function:

    int myFun(int a, int b) {
    // function body
    return result;

How to call Function:

//calling function myFun() with two parameters
myFun(passParameter 1,passParameter 2);

How to define Function:

int myFun(int a, int b) {
    // Write a function body to define the function
    return result;


Working of the Online C Compiler

The online C compilers work in various stages for analysing source code to output code. Despite their variations, they usually perform the below actions:

  • Lexical Analyser: It separates the source code into lexemes. Lexemes are individual pieces of code. It represents specific coding patterns.
  • Syntax Analyser: It checks the syntax of the code. Checking is done based on the rules for the source code. This method is also known as parsing.
  • Semantic Analyser: The logic of the code is tested by the online C compiler for accuracy. By verifying the accuracy of the code, this phase extends beyond syntax analysis.
  • Intermediate Code Generation: After the code has gone through all three analysis methods, the online C compiler creates an IR code of the source code.
  • Optimisation: It optimises the IR code. Then the compiler will determine the kind and degree of optimization and generate the output code.
  • Output Generation: It creates the final output code. Using the optimised IR code.

To access the abilities of our online c compiler, you must first Sign in. Our online c compiler works in the following ways:

  • Code Editor: Use the code editor to enter code. You can modify code easily. Syntax highlighting is available for high readability.
  • RUN: After entering C code in the editor and choosing the correct compiler version. Users can click the "RUN CODE" button and run their C program.
  • Reset Code: To reset the C code entered into the editor. Click the "reset" button in the top right corner of the editor.
  • STDIN & STDOUT: Users can utilise our compiler's Standard Input (stdin) console to feed input to the C Code. And the Standard Output (stdout) of the compiler displays the output of the code.


How to write and run the c programs online?

Online C compilers are websites where you may create your code. Then we send it to a server that already has an inbuilt compiler. As a response, the result is obtained and rendered on the client side.

The C code can be easily compiled using the Coding Ninjas Studio's online compiler. Enter the code in the editor and press "RUN CODE." Then the program will run and be compiled. The output is shown on the standard output console.


Benefits of using Online C Compiler

Some of the benefits of using an online c compiler are as follows:

  • Enhanced performance.
  • No Setup is needed.
  • We can access it from anywhere.
  • Decrease in system load.
  • Source code and program protection.
  • Increased output and accuracy.
  • Compile time portability of programs.



  • Compiler: A compiler is an essential tool that can be used locally or online for compiling a code, that is, converting the code to a machine based language for output.
  • Interpreter: An Interpreter is a tool that works similarly to a compiler, converting high level code into machine based language, but it converts the code line by line rather than in a single pass.
  • Online IDE: Online IDE, or Integrated Development Environment, is a software based tool that is used as a single platform for all kinds of computer programming. It consists of an integrated compiler or interpreter, extensions, dependency files, and a debugger. Example: Eclipse
  • Code Editor: A Code Editor is another essential part of computer programming. It is a place where all source codes can be created and modified. It can be a stand alone application or part of an IDE. Example: Vim and Sublime
  • Coding Ground: Coding Ground is a tool that provides easy accessibility to developers for using more than one programming language, technology, and framework. It allows developers to use various tools on a single platform.