What are the keywords in C language

What are the c language keywords?

C language keywords are also called reserved words, which are words that have been used by the C language itself and cannot be used for other purposes.

C language is concise, compact, easy to use and flexible. The ANSI C standard C language has a total of 32 keywords and 9 control statements. The program can be written in free form and is case-sensitive. Combine the basic structures and statements of high-level languages ​​with the practicality of low-level languages. C language can operate on bits, bytes and addresses just like assembly language, and these three are the most basic working units of computers.

There are 32 keywords in C language. According to the function of keywords, they can be divided into four categories: data type keywords, control statement keywords, storage type keywords and other keywords.

Recommended: "C Language Tutorial"

1 Data type keywords (12):

(1) char: declare character variables or function (2) double: declare a double precision variable or function (3) enum: declare an enumeration type (4) float: declare a floating point variable or function (5) int: declare an integer variable or function (6) long: Declare a long integer variable or function (7) short: declare a short integer variable or function (8) signed: declare a signed type variable or function (9) struct: declare a structure variable or function (10) union: declare a union (Union) data type (11) unsigned: declare an unsigned type variable or function (12) void: declare a function with no return value or parameters, declare an untyped pointer (basically these three functions)

2 Control statement keywords (12):

A loop statement (1) for: a loop statement (can be understood but not expressed) (2) do: the loop body of the loop statement (3) while: Loop conditions of loop statements (4) break: jump out of the current loop (5) continue: end the current loop and start the next cycle B conditional statement (1) if: conditional statement (2) else: conditional statement negates the branch (used with if ) (3) goto: unconditional jump statement C switch statement (1) switch: used for switch statements (2) case: switch statement branch (3) default: "other" branch in the switch statement D return statement return: subroutine Return statement (can take parameters or not)

3 Storage type keywords (4)

(1)auto: Declaring automatic variables is generally not used (2)extern: Declared variables are declared in other files (can also be regarded as reference variables) (3)register: declare accumulator variables (4)static: declare static variables

4 Other keywords (4):

(1)const: declare a read-only variable (2)sizeof: calculate the length of the data type (3)typedef: used to alias the data type (of course there are other functions) (4)volatile: indicate that the variable is in the program Can be changed implicitly during execution

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