Camp 1 · Schritt 2 von 12
Hello, World!
The original Hello World — from the book that taught the world to program — line by line.
The phrase "Hello, World!" as a first program comes from The C Programming Language (1978). You're about to run the ancestor of every Hello World ever written.
The program
Every piece decoded
#include <stdio.h>
A preprocessor directive that pulls in the standard input/output
library — which provides printf. Without it, C wouldn't know how to
print. The #include lines always sit at the top.
int main(void)
Every C program's entry point. int means it returns an integer;
(void) means it takes no arguments.
printf("Hello, World!\n");
Prints text. The \n is a newline — C won't add one for you (unlike
Python's print). Leave it out and the next output crowds onto the same
line.
return 0;
Hands 0 back to the operating system, meaning "success". Non-zero
signals an error. This is a convention the whole OS relies on.
The details C insists on
- Every statement ends with
; - Text needs the
\nfor line breaks — spell them out mainreturningintand ending withreturn 0;is the standard shape
What does the newline escape do in printf("Hi\n"); ?
Why is #include <stdio.h> needed?
What's next
The compile step in detail — what actually turns your .c file into a running program.