If you are really starting to study computers for the first time, you may find it a bit difficult because it covers a lot of basic knowledge other than the C language, but it is a very detailed course and good for laying the foundation.

ironmiken

This is a newly developed introductory programming course starting with C, created thanks to the support for 'TBC++'.
Upgrade your programming life with 'TBC'.

honglab

Hong Jung-mo's C Programming: Learning by Doing

입문

초급

중급이상

C언어

How Computers Work for Beginner Programmers

Let's start slowly

Introducing the C language

Data and C Language

String and formatted input/output

Operators, expressions, statements

Loop

branch

Character Input/Output and Input Validation

Function

Arrays and Pointers

String functions

Storage Classes, Linkage and Memory Management

File Input/Output

Structure

Handling beets

Preprocessors and libraries