Basic concepts.

Comments
ASCII chart
Translation phases
Identifier - Scope - Lifetime
Lookup and Name Spaces
Type - Arithmetic types
Objects and Alignment
The main function
As-if rule
Undefined behavior
Memory model and Data races
.

Keywords.

Preprocessor.

#if - #ifdef - #ifndef
#define - # - ##
#include - #pragma
#line - #error
.

Statements.

if - switch
for
while - do-while
continue - break
goto - return
.

Expressions.

Value categories
Evaluation order and sequencing
Constants and literals
Integer constants
Floating constants
Character constants
String literals
Compound literals(C99)
Constant expressions
Implicit conversions
Operators
Member access and indirection
Logical - Comparison
Arithmetic - Assignment
Increment and Decrement
Call, Comma, Ternary
sizeof - _Alignof(C11)
Cast operators
Operator precedence
Generic selection(C11)
.

Initialization.

Scalar
Array
Structure/Union

Declarations.

Pointers - Arrays
Enumerations
Storage duration and Linkage
const - volatile - restrict(C99)
struct - union - Bit fields
_Alignas(C11) - typedef
_Static_assert(C11)
Atomic types(C11)
External and tentative definitions
.

Functions.

Function declaration
Function definition
inline(C99) - _Noreturn(C11)
Variadic arguments
.

Miscellaneous.

History of C
Conformance
Inline assembly
Signal handling
Analyzability(C11)
.