var x=1; for(;x<6;x+=2){ x=x*x; } alert(x); //output= 11 //do u have any explanation?

Answer 1

var x = 1;

for(; x < 6; x +=2) {
x=x*x;
}

alert(x);

First x is declared outside the for loop so that the alert call will be able to access it;

When it hits the loop the setup part of the loop "for(;" is empty so it is skipped and the conditional part "x < 6;" is checked.

Here x is 1 so 1 < 6 is true and the body {x=x*x;} is executed.

x = 1*1; x is still equal to 1 at the end of the loop body.

Then the incrementation part "x += 2" is ran 1+2 = 3, x equals 3.

Now the conditional is checked again 3 < 6 is true so the body is ran again.

3 * 3 = 9. Then the incrementation part of the loop is ran again 9 + 2 = 11.

Then the conditional is checked 11 < 6 is false so the loop exits and the alert is ran with the output of 11.

Answer 2

x=1: x=1*1;
x=1: x+=2;
x=3: x=3*3;
x=9: x+=2
x=11: x<6 == false