Standard Input / Output (`stdio.h`)

The <stdio.h> library provides the core I/O functions.

Function	Purpose
printf	Formatted output to stdout.
scanf	Formatted input from stdin.
fprintf/fscanf	I/O to/from a FILE*.
fgets	Read a line safely (avoids buffer overflow).
puts	Write a string followed by \n.
getchar / putchar	Single‑character I/O.

Always check the return value of scanf/fgets to verify that input succeeded.