Conditional Statement & Loops

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Conditional Statement & Loops Control structure is the essential part of programming

language.Commonly used control structures are:

Selection statement

If

IfelseIfelseif

Nested if

While

Do-whileFor

Switch case

Break

Continue


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Selection statement

The syntax of if is

If(condition)

Statement if the condition is true

The syntax of ifelse isIf(condition)


else

Statement if the condition is false


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The syntax of ifelse if is

If(condition)


else If(condition)

Statement if the another condition is false

else If(condition)

Statement if the another condition is false

else

Statement


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Nested if

If(condition)


If(condition)


else

Statement if the condition is false


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If else statement

if else Demo

var a,b,c;

a=10;b=20;c=30;

if(a>b)

{

if(a>c)

document.write(" a is largest

number ");

else

document.write(" c is largest

number ");}

else

{

if(b>c)

document.write(" b is largestnumber ");

else

document.write(" c is largestnumber ");

}


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If else if statement

if else if Demo

var marks;

marks=80;

if(marks=40 && marks=60 &&marks


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Display Even or Odd

Odd or Even Demo

function fun(str)

{var num=Number(str);

if(num%2==0)

alert("Even number!!!");

elsealert("Odd number!!!");

}

var input_str=prompt("Entersome number","");

fun(input_str);


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Display the Message Using Time

Condition

Display Message

function GreetMsg()

{

var today=new Date();

var h=today.getHours();

var m=today.getMinutes();

var s=today.getSeconds();

if(h


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While statement

Used to implement the iterative logic of theprogram.

Syntax:

Some initial condition;

While(terminating condition)

{

Some statements;

Stepping condition;

}


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While Demo

i=1;

while(i


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Do While statement

Syntax:Do

{

}while(condition)


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Do-While Demo

counter=1;

do

{

document.write("Thisstatement

number:"+counter);

document.write("
");

counter++;

}while(counter


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For loop statement

Syntax:

For(initial condition; terminating condition;

stepping condition)


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for-loop Demo

NumberSquare

for(i=1;i


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Switch statement

Syntax:Switch(ch)

{

Case 0: statement1;

Break;Case 0: statement2;

Break;

Case 0: statement3;Break;

}


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document.write("May");

Break;

Case 6:

document.write("june");

Break;

Case 7:

document.write("july");Break;

Case 8:

document.write("august");

Break;

Case 9:

document.write("september");

Break;Case 10:

document.write("october");

Break;

Case 11:

document.write("november");

Break;

Case 12:document.write("december");

Break;

}

switch case Demo

d=new Date();

ch=d.getMonth();

switch(ch)

{

Case 1:

document.write("January");

Break;

Case 2:

document.write("February");

Break;

Case 3:

document.write("March");

Break;

Case 4:

document.write("April");

Break;

Case 5:


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Break statement

Break Demo

for(i=10;i>=0;i--)

{

if(i==5)

break;

}

document.write("My

Lucky Number is"+i);


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Break statement

Continue Demo

for(i=10;i>=0;i--)

{

if(i==5)

{

x=i;continue;

}

document.write(i);

document.write("
");}

document.write("The Number"+x+" is missing in abovelist");


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Conditional Statement & Loops

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