Elements of C: Variables , Constants, Operators

 Variables

Variable is a name of  storage location in the memory that contains data and can be modified during program execution. We can understand like this , while declaring variable we are keeping space for some value. Each variable in C language should be unique. Before using any variable we must declare it before.

Rules for naming variable

i. Starting character must be any letter or underscore ( _ ) and ends with letter or digit.

ii. Variable name must be unique.

iii. keywords of C should not be used as variable.

iv. Variable name can be both uppercase and lowercase.

v . No other special characters can be used except letters, digits and underscore.

Declaring a variable

int x;

int a, b, c, d;

Constants

Constants are those value which remains same in the program and never change during executing of program. Types of constant in C language are integer constants, character constants, real constants and string constants.

Ex:

int num = 100;

char a = 'a';

float ab = 90.0342;

char name = "Hello";

Operators

Operators are special symbols which have special meaning in the program. They can operates mathematical and logical operation. Types of operators in C language:

Arithmetic operator: +, -, *, /, %

Compound assignment operators: =, -=, +=, *=, /=, %=

Relational operator: ==, < , > <=, >=, !=

Logical operator : && (and), || (or), !(not)

Unary operator: ++, --

Ternary operator: ?, : (Ex: h = (a< b)?a:b)