C language

  C Identifiers C identifiers represent the name in the C program, for example, variables, functions, arrays, structures, unions, labels, etc. An identifier can be composed of letters such as uppercase, lowercase letters, underscore, digits, but the starting letter should be either an alphabet or an underscore. If the identifier is not used in the external linkage, then it is called as an internal identifier. If the identifier is used in the external linkage, then it is called as an external identifier. We can say that an identifier is a collection of alphanumeric characters that begins either with an alphabetical character or an underscore, which are used to represent various programming elements such as variables, functions, arrays, structures, unions, labels, etc. There are 52 alphabetical characters (uppercase and lowercase), underscore character, and ten numerical digits (0-9) that represent the identifiers. There is a total of 63 alphanumerical characters that represent t...

  Keywords in C A keyword is a  reserved word . You cannot use it as a variable name, constant name, etc. There are only 32 reserved words (keywords) in the C language. A list of 32 keywords in the c language is given below: 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 We will learn about all the C language keywords later.

  Data Types in C A data type specifies the type of data that a variable can store such as integer, floating, character, etc. There are the following data types in C language. Types Data Types Basic Data Type int, char, float, double Derived Data Type array, pointer, structure, union Enumeration Data Type enum Void Data Type void Basic Data Types The basic data types are integer-based and floating-point based. C language supports both signed and unsigned literals. The memory size of the basic data types may change according to 32 or 64-bit operating system. Let's see the basic data types. Its size is given  according to 32-bit architecture . Data Types Memory Size Range char 1 byte −128 to 127 signed char 1 byte −128 to 127 unsigned char 1 byte 0 to 255 short 2 byte −32,768 to 32,767 signed short ...

  Variables in C A  variable  is a name of the memory location. It is used to store data. Its value can be changed, and it can be reused many times. It is a way to represent memory location through symbol so that it can be easily identified. Let's see the syntax to declare a variable:   1.       type variable_list;   The example of declaring the variable is given below: 1        int  a;   2.       float  b;   3.       char  c;   Here, a, b, c are variables. The int, float, char are the data types. We can also provide values while declaring the variables as given below:   1.       int  a=10,b=20; //declaring 2 variable of integer type    2.       float  f=20.8;   3.   ...