Online C Compiler — Write, Compile & Run C Code
CodePocket provides a free online C compiler powered by GCC 13. Learn core computer science fundamentals, dynamic memory management (malloc/free), pointers, and system routines right from your web browser.
> Output (18ms): Fibonacci Series (10 terms): 0 1 1 2 3 5 8 13 21 34 > [Process exited with code 0]
Why use CodePocket for C Development?
CodePocket provides an isolated, zero-configuration cloud container environment for writing and running C code. Whether you are learning core language fundamentals, preparing for technical coding interviews, or testing algorithm prototypes, CodePocket delivers instant execution feedback without local setup.
Standard C17 Specification
Compliant with ISO C17 standard and GCC extensions for low-level memory programming.
Interactive STDIN (scanf)
Test interactive programs using scanf(), fgets(), and getchar() with live stream input.
Standard C Library
Full access to <stdio.h>, <stdlib.h>, <string.h>, <math.h>, and standard headers.
Common C Errors & Quick Fixes
Cause: Dereferencing NULL or uninitialized pointers, or forgetting & in scanf("%d", &var).
Fix: Always pass the memory address &var to scanf and check malloc return values.
Cause: Using library functions without including the corresponding header file (e.g. using malloc without <stdlib.h>).
Fix: Include the required header at the top: #include <stdlib.h>.
Cause: Missing semicolon at the end of a statement.
Fix: Ensure every statement terminates with a semicolon ;.