Keywords

MamtaWardhani's avatar
Published Jan 25, 2025
Contribute to Docs

In C programming, keywords are fundamental building blocks. They are predefined and reserved by the language for specific functionalities, making it easier for programmers to write efficient and standard code. Keywords are part of the syntax and convey the compiler how to interpret a piece of code. Since they are reserved, they cannot be redefined or used for any other purpose.

C provides a small set of keywords compared to modern programming languages, ensuring simplicity and performance. Understanding keywords is essential for learning the language and using its features effectively.

Key points about keywords

  • Keywords are case-sensitive in C. For example, if and If are treated differently.
  • There are 32 standard keywords in C.
  • Keywords cannot be used as variable names, function names, or any other identifiers.
  • They provide specific instructions to the compiler to perform operations like branching, looping, data type definition, and memory management.
  • Some compilers may introduce additional keywords as extensions, but these are non-standard.

Table of Keywords

Keyword Description
auto Declares an automatic variable
break Exits a loop or switch statement
case Defines a branch in a switch statement
char Declares a character variable
const Declares a constant value
continue Skips the current iteration of a loop
default Defines the default branch in a switch
do Starts a do-while loop
double Declares a double-precision floating point
else Provides an alternative branch in an if
enum Defines an enumeration
extern Declares an external variable
float Declares a floating-point variable
for Starts a for loop
goto Transfers control to a labeled statement
if Starts a conditional statement
int Declares an integer variable
long Declares a long integer variable
register Declares a register variable
return Exits from a function
short Declares a short integer variable
signed Declares a signed variable
sizeof Determines the size of a data type
static Declares a static variable
struct Declares a structure
switch Starts a switch statement
typedef Defines a new type name
union Declares a union
unsigned Declares an unsigned variable
void Declares a void type
volatile Declares a variable that can be modified externally
while Starts a while loop

Keywords in C are indispensable for writing efficient and functional programs. They form the backbone of the language’s syntax and provide instructions to the compiler for various operations. Understanding these reserved words is crucial for any programmer learning C, as it helps in creating structured and standard-compliant code. By mastering the use of keywords, you can unlock the full potential of the C programming language.

Keywords

typedef
Defines a new name for an existing data type in C to improve code readability and maintainability.

All contributors

Contribute to Docs

Learn C on Codecademy