Variables in C

Introduction Generations of Computers Classification of Computers Basic Anatomy of a Computer System Memory Management Computer Software Operating System

Algorithm Flowcharts

Programming Language Generations of Programming Languages Introduction to C Structure of C Programming Language Integrated Development Environment First C program, Hello World Executing a C Program Constants in C Variables in C C Storage Classes and Storage Class Specifiers

Introduction Arithmetic operators Relational Operators Logical Operators Assignment Operator Increment and Decrement Operators Conditional Operators Bitwise Operators Precedence and Associativity

Control Instructions in C if Statement in C if-else Statement Nested if-else statement else if ladder Switch Statements in C

Loops Introduction for Loop while loop in C do-while Loop break and continue statements

Array in C One Dimensional array Two Dimensional Array Multidimensional Arrays

Modular Programming Functions

Searching Techniques Linear Search Algorithm Binary-Search-Algorithm

Sorting Introduction Bubble Sort

What is Strings Standard Library String Functions

Structure Introduction Defining a Structure Declaration of Structure Example of Structure Union Introduction Defining a Union Accessing Union Members

Pointers in C Accessing the Address of a variable Pointer Operations

Dynamic Memory Allocation

A Variable is a data name that may be used to store a data value. A variable may take different values at a different time during execution.

Variable names are names given to locations in memory. These locations can contain integer, real or character constants. In any language, the types of variables that it can support depend on the types of constants that it can handle.

Variable names consist of letters, digits, and the underscore character.

Rules for Constructing Variable Names

A variable name is any combination of 1 to 31 alphabets, digits or underscores. Some compilers allow variable names whose length could be up to 247 characters. Still, it would be safer to stick to the rule of 31 characters. Do not create unnecessarily long variable names as it adds to your typing effort.
Uppercase and lowercase are significant. That is the variable Name is not same as name of NAME.
The first character in the variable name must be an alphabet or underscore.
No commas or white space are allowed within a variable name.
No special symbol other than an underscore

Example of the valid variable name:

- Name
- john
- Delhi
- Sum_1
- _dis1

Example of the invalid variable name:

- 123
- int
- (abc)

Fundamentals of the Computer System

Introduction to Algorithm

Programming Basics

Operators in C

Conditional Branching

Iteration and Loops

Array in C

Functions in C

Searching Algorithms

Sorting Algorithms

Strings

Structures and Union

Pointers in C

File Handling in C

Advanced

Variables in C

Rules for Constructing Variable Names

Example of the valid variable name:

Example of the invalid variable name: