Keyword, whitespsce in c and data types of C language



                     Keywords is a predefined or reserved word in C library with a fixed meaning and used  to perform  an internal operation. C language support 32 keywords. These reserved words  may not be used a constant or variables or any other identifier  names. The following list shows the reserved  words in C.

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

Witespace in C
                             A line containing only whitespace, possibly with a comment, is known as a blank line and a C compiler totally ignores it. Whitespace is the term used in C to describe blanks, tabs, newline characters and comments. Whitespace separates one part of a statement from another and enables the compiler to identify where one element in a statement, such as int, ends and the next element begins. Therefore, in the following statement int age;
 there must be at least one whitespace character (usually a space) between int and age for the compiler to be able to di statement stinguish them. On the other hand, in the following statement-

fruit = apples + oranges; //get the totol fruit

no whitespace c although you are free to includ an apples e some if you wish to increase readability.

Data Types 
Data types in C refer to an extensive system used for declaring variables or functions of different types. The type of a variable determines how much space it occupies in storage and how the bit pattern stored is interpreted.

 C data types are used to: 

  • Identify the type of a variable when it declared.
  •  Identify the type of return value of a function. 
  • identify the type of a parameter expected by a function. 
Data types available in C language are:

  •  Built-in Data Types . .
  •  fundamental data types (word, in, hae, double, fat and pointer)
  •  Derived data types (array, string and structure) 
  • Programmer - defined Data types (structure, union and enumeration) 
Fundamental Data Types

void Used to denote the type with no values.
int Used to denote an integer type
char Used to denote a charcter type
float, double Used to denote a floating point type
int*, float *, char * Used to denote a pointer type

Derived Data types

array A finite sequence (or table) of variables of the same data type.
string An array of character variables.
structure A collection of related variables of the same and/ or different data types.

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