List of all Keywords in C Language | Keywords in C | C Programming

Keywords in C Language | C Programming

Keywords in C Language:

The C programming language, according to the C99 standard, includes 32 keywords. These keywords are reserved words with specific meanings to the compiler and cannot be used as identifiers (like variable names or function names).

auto	break	case	char
const	continue	default	do
double	else	enum	extern
float	for	goto	if
int	long	register	return
short	signed	sizeof	static
struct	switch	typedef	union
unsigned	void	volatile	while

Description of all Keywords in C: 

auto

The auto keyword declares automatic variables. For example:

auto int var1;

This statement suggests that var1 is a variable of storage class auto and type int.

Variables declared within function bodies are automatic by default. They are recreated each time a function is executed.

break and continue

The break statement terminates the innermost loop immediately when it's encountered. It's also used to terminate the switch statement.

switch, case and default

The switch and case statement is used when a block of statements has to be executed among many blocks.

char

The char keyword declares a character variable. For example:

char alphabet;

Here, alphabet is a character type variable.

const

An identifier can be declared constant by using the const keyword.

double and float

Keywords double and float are used for declaring floating type variables. For example:

float number;

double longNumber;

Here, number is a single-precision floating type variable whereas, longNumber is a double-precision floating type variable.

if and else

In C programming, if and else are used to make decisions.

enum

Enumeration types are declared in C programming using keyword enum. 

For example:

enum suit

{

    hearts;

    spades;

    clubs;

    diamonds;

};

Here, an enumerated variable suit is created having tags: hearts, spades, clubs, and diamonds.

extern

The extern keyword declares that a variable or a function has external linkage outside of the file it is declared.

for

There are three types of loops in C programming. The for loop is written in C programming using the keyword for.

goto

The goto statement is used to transfer control of the program to the specified label

int

The int keyword is used to declare integer type variables. 

short, long, signed and unsigned

The short, long, signed and unsigned keywords are type modifiers that alter the meaning of a base data type to yield a new type.

return

The return keyword terminates the function and returns the value.

int func() {

    int b = 5;

    return b;

}

This function func() returns 5 to the calling function. 

sizeof

The sizeof keyword evaluates the size of data (a variable or a constant).

register

The register keyword creates register variables which are much faster than normal variables.

static

The static keyword creates a static variable. The value of the static variables persists until the end of the program.

struct

The struct keyword is used for declaring a structure. A structure can hold variables of different types under a single name.

typedef

The typedef keyword is used to explicitly associate a type with an identifier.

union

A union is used for grouping different types of variables under a single name.

void

The void keyword meaning nothing or no value.

volatile

The volatile keyword is used for creating volatile objects. A volatile object can be modified in an unspecified way by the hardware.