Module 3 - Variables & Expressions

Module 3: Variables & Expressions By SRIRAM . B

Overview 

Variables

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DataTypes

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Operators 

Arithmetic

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Relational

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Logical

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Conditional / Ternary Operators

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Unary Operators

Variables 

Variables are fundamental to any programming language.

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Values can be assigned to variables and changed during program execution.

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The value assigned to a variable is stored in the memory location represented by the variable name.

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Syntax : ;

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A variable can be declared as given below. int var1; where int represents the data type, and var1 is the name given to the variable.

DataTypes Data types are used for the actual representation of data in the memory. C-Sharp supports two kinds of data types: 

Value types • bool • char, string • byte, short ,int, long • Float, double, decimal • enum types • struct types

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Reference types • Class types • Interface types • Array types

Example 1 :- Using Variable and Data types.. using System; class Hello { public static void Main(){ //Variable declaration int ivar; float fvar; char cvar; //Variable initialization ivar=10; fvar=100.05f; cvar=‘A’;

Example 1 :- Using Variable and Data types.. //Display the contents of variables Console.WriteLine("Value stored in int variable is:{0}",ivar); Console.WriteLine("Value stored in float variable is:{0}",fvar); Console.WriteLine("Value stored in character variable is:{0}",cvar); } }

Output Output of the code is: Value stored in int variable is :10 Value stored in float variable is:100.05 Value stored in character variable is:A

Example 2 :- Using String Data type The string data type is used for storing a stream of characters. using System; class use_string { public static void Main() { string name="Jolly"; Console.WriteLine("Name is {0}",name); } } Output of the code is:

Name is Jolly

Operators Operators indicate the type of operation to be performed on the operands in a given expression. They can be classified based on their functionality as follows: 

Arithmetic Operators 

In addition to the four operators +, -, * and /, C-Sharp also provides the remainder or modulo operator represented by the symbol %.

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The modulo operator returns the remainder when an integer is divided by another.

Using % Operator //Using the modulo operator using System; class use_modulo { public static void Main() { int var1=11,var2=5,var3; var3=var1%var2; Console.WriteLine("Remainder is{0}",var3); } } Output of the above code is: Remainder is1

Example - Arithmetic Assignment Operators Arithmetic assignment operators combine an arithmetic operator (+,-,*,/,%) and the assignment operator (=). //Using the arithmetic assignment operator using System; class arithmetic_assignment { public static void Main() { int var1=10,var2=5;

Example - Arithmetic Assignment Operators.. var1+=var2; Console.WriteLine("Value in var1 is {0}", var1); } } Output of the code is: Value in var1 is 15

Relational Operators Relational operators are used to compare two values. The result of the comparison is either true or false. Some of the relational operators are:

Operator

Meaning

>

Greater than

<

Less than

==

Equal to

!=

Not equal to

>=

Greater than or equal to

<=

Less than or equal to

Logical Operators 

Logical operators are used to combine two or more conditions in expressions.

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The conditional logical operators are also known as short-circuit logical operators.

Examples of logical operators are:

Operator

Meaning

&&

Evaluates to true only if both conditions are satisfied

||

Evaluates to true if any one of the condition is satisfied

!

Evaluates to true if condition is false and vice versa

Operator Precedence and Associativity 

Operator precedence represents the order of execution of the different operations in a given expression.

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The associativity of the operators represents the direction from where the execution begins.

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Operators can have: 

Right associativity or

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Left associativity

Conditional / Ternary Operator It operates on three operands using System; class Hello {

public static void Main() { int var1=20,var2; var2=(var1>10)?30:40; }

}

Unary Operators 

The unary operators operate on a single operand.

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Examples of unary operators are: 

Increment operator (++) – increments the value of a variable by one.

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Decrement operator (--) – decrements the value of a variable by one.

Prefix and Postfix Notations 

The increment and decrement operators can be used in two ways: 

Prefix – where the operator precedes the variable: ++Var;

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Postfix – where the operator follows the variable Var++;

Example 1 : Prefix and Postfix Notations using System; class prefix { public static void Main() { int var1,var2; var1=10; var2=++var1; Console.WriteLine("Var1:{0}",var1); Console.WriteLine("Var2:{0}",var2); } } Output of the code is: Var1:11 Var2:11

Example 2 : Prefix and Postfix Notations using System; class postfix { public static void Main() { int var1,var2; var1=10; var2=var1++; Console.WriteLine("Var1:{0}",var1); Console.WriteLine("Var2:{0}",var2); } } Output of the code is: Var1:11 Var2:10

Variables & Expressions - Flashback 

Variables

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DataTypes



Operators 

Arithmetic



Relational



Logical

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Conditional / Ternary Operators



Unary Operators

Session Ends

Exercise

Relax