Snail on the well

Question

Help! I can not understand why the algorithm is not executed? If i<=depth the loop is sometimes run again. What have I done wrong?

function main() {
var depth = parseInt(readLine(), 10);
for (i=0, n=0 ; i <= depth; i-=2){
i+=7;
n++;
} console.log(n);
}

Answer 1

The i -= 2 is it done before or after the i <= depth. I think before.

Answer 2

Shouldn't it be:

if (i >= depth) {
break;
}

Answer 3

Thank you! I added an "if" to the loop and it worked.

...
if ( i <= depth)
break;
}
...

Only nothing worked, if I left the "i <= depth" condition in the "for" loop, everything ended on the first run, why?