for loop structure and full explain with example

Why For Loops?

1) Like all loops, "for loops" execute blocks of code over and over again.
2) The advantage to a for loop is we know exactly how many times the loop will execute before the loop starts.

Syntax

for(initialization; condition; increment/decrement)

{

  Statements;

}

Example:

for(i=0;i<=5;i++)

{

  statements;

}

Flow chart of for loop:
     In the following flowchart is draw similar to the above example, don't forget to see the whole explanation about the flowchart.

Step 1:
     Start Initialization, if you want to initialize  any value you can assign here this is optional.

Step 2:
     Conditions are return true or false value this also optional, some examples are

Conditions
3>5        => return False
6<=6     =>  return True
3==3     =>  return True

Symbols
<           => Less than
>           => Greater than
=           => Equal
<=         => less than or equal
>=         => greater than or equal
!            => Not
!=          => Not equal

     If true then inside the for loop statements executed.

Step 3:
     Statement, in this part have any type of statements like alert, function calling, if, for and etc. Then next it will go to increments/Decrements part.

Step 4:
     Increment/Decrements this is also optional and here we can increase or decrease the value. Then go to check the condition again.

Step 5:
     Condition again check and repeat the process again, when the condition is return false value the control will go to Next Statements.

for(i=0;i<=5;i++)

{

  alert(i);

}

     Below I write all the execution steps, if you new to for loop please watch all steps.

start
i=0

i<=5  (0<=5)   => True
alert the i value (alert 0)
i++ [i=i+1]  (i=0+1)  [i=1]

i<=5    (1<=5)   => True
alert 1
i++  (i=1+1)  [i=2]

i<=5   (2<=5)  => True
alert 2
i++ (i=2+1)  [i=3]

i<=5  (3<=5)  => True
alert 3
i++  (i=3+1)  [i=4]

i<=5  (4<=5) => True
alert 4
i++  (i=4+1)  [i=5]

i<=5   (5<=5)  => True
alert 5
i++  (i=5+1)  [i=6]

i<=5   (6<=5)   => False

Then go to outside of the for loop.

Example Program:- (Editor)

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Output:-

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