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C — Hello World

The classic hello-world in C — an include, main, and printf — for testing highlighters, C compilers, and parsers against the canonical first program.

Syntax highlighting Code parsing Editor testing

Preview — first 8 linesc

/* The classic first program, in C. */
#include <stdio.h>

int main(void) {
    printf("Hello, world!\n");
    return 0;
}

Specifications

Language: C
Kind: hello-world
Lines: 7
Encoding: UTF-8
Line Endings: LF

Testing contract

Expected to pass

Scenario: Compile the file with a C99 or later compiler and run it.
Expected result: It compiles with no warnings under `-Wall -Wextra` and prints exactly `Hello, world!` and a newline, returning exit status 0. `main` is declared `(void)`, so it is also valid C89.

What is a .c file?

C (.c) is a plain-text source file for the C programming language — a low-level, statically typed, compiled language that maps closely to hardware. It underpins operating systems, embedded firmware, and language runtimes, using manual memory management, pointers, structs, and the preprocessor.

How to use this file

Use an example .c file to test syntax highlighters, C compilers (gcc, clang) and their diagnostics, static analysers, formatters (clang-format), and parser or highlighting tooling.

How to use this file for testing

“C — Hello World” is a deterministic Novus Examples fixture for Syntax highlighting, Code parsing, Editor testing. Idiomatic hello-world programs and realistic snippets across sixteen languages, exercising comments, string escapes, interpolation, numeric literals, and language keywords — for testing syntax highlighters, editor themes, and tree-sitter grammars.

Documented properties for this file: C · UTF-8 · LF. Compare results against paired or grouped companions on this page when present (clean↔damaged, searchable↔scanned, or format twins) so scores stay reproducible across runs.

Download the file once, keep the path stable in CI or local scripts, and treat the spec table as the contract: dimensions, seeds, field lists, and roles are intentional. Corrupt or invalid samples are labelled as such — expect parsers to fail loudly rather than silently accept them.

This is a short, known-correct source file. Run it through your syntax highlighter, linter, formatter, tree-sitter grammar, or parser, and open it in the in-browser editor to tweak and re-download. Each snippet exercises comments, string escapes, literals, and language keywords.