C language

 

C

Language

Standard Library

Type support

Dynamic memory management

Error handling

Program utilities

Date and time utilities

Strings library

Algorithms

Numerics

Input/output support

Localization support

Thread support (C11)

Atomic operations (C11)

 

C language

General topics
Preprocessor
Comments
Keywords
Escape sequences
History of C
Flow control
Conditional execution statements
if statement	switch statement
Iteration statements
for loop	while loop do-while loop
Jump statements
continue statement break statement	goto statement return statement
Functions
function declaration
inline specifier
Types
fundamental types pointer types compound types enumeration types	union types function types
Specifiers
cv specifiers
storage-class specifiers
alignas specifier (C99)
function specifiers (C99)
Literals
integer literals character literals floating-point literals	string literals boolean literals(C99)
Expressions
order of evaluation
operators
operator precedence
alternative operators
Utilities
typedef declaration
attributes (C99)
casts
Miscellaneous
Inline assembly

 

This is a brief reference of available C constructs.

Flow control

Conditional execution statements

Different code paths are executed according to the value of given expression

• if executes code conditionally
• switch executes code according to the value of an integral argument

Iteration statements

The same code is executed several times

• for executes loop
• while executes loop, checking condition before each iteration
• do-while executes loop, checking condition after each iteration

Jump statements

Continue execution at a different location

• continue skips the remaining part of the enclosing loop body
• break terminates the enclosing loop
• goto continues execution in another location
• return terminates execution of the enclosing function

Functions

The same code can be reused at different locations in the program

• function declaration declares a function
• inline specifier hints the compiler to insert a function's body directly into the calling code

Types

• fundamental types defines basic character, integer and floating point types
• pointer types, holding a memory location
• compound types defines types that can hold several data members
• enumeration types defines types that are able to hold only one of the specified values
• union types defines types that can hold data in several representations
• function types define function call signatures, that is the types of arguments and the return type

Specifiers

• cv specifiers specifies constness and volatility of a type
• storage-class specifiers specifies storage duration and linkage of a type
• alignas specifier specifies that the storage for the variable should be aligned by specific amount (since C99)
• function specifiers specifies how the compiler should handle a function (since C99)

Literals

Literals are the tokens of a C program that represent constant values, embedded in the source code.

• integer literals are decimal, octal, or hexadecimal numbers of integer type.
• character literals are individual characters of type char, char16_t, char32_t, or wchar_t.
• floating-point literals are values of type float, double, or long double
• string literals are sequences of characters, which may be narrow, multibyte, or wide.
• boolean literals are values of type bool, that is true and false (since C99)
• user-defined literals are constant values of user-specified type (since C99)

Expressions

An expression is a sequence of operators and operands that specifies a computation. An expression can result in a value and can cause side effects.

• order of evaluation of arguments and subexpressions specifies the order in which intermediate results are obtained.
• operators allow the use of syntax commonly found in mathematics

Common operators
assignment	increment decrement	arithmetic	logical	comparison	member access	other
a = b a += b a -= b a *= b a /= b a %= b a &= b a |= b a ^= b a <<= b a >>= b	++a --a a++ a--	+a -a a + b a - b a * b a / b a % b ~a a & b a | b a ^ b a << b a >> b	!a a && b a || b	a == b a != b a < b a > b a <= b a >= b	a[b] *a &a a->b a.b	a(...) a, b (type) a ? : sizeof _Alignof (since C11)

• operator precedence is the order in which operators are bound to their arguments
• alternative representations exist for some of the operators

Utilities

Types

• typedef declaration creates a synonym for a type
• attributes defines additional information about variable (since C99)

Casts

• standard conversions implicit conversions from one type to another

Miscellaneous

• main function
• Inline assembly

See also

C++ documentation for C++ language constructs