Why we use I++ ,+i and --i

Question

Solve

Answer 1

They're used to increase or decrease the value by one
for ex.
i=0
i++
Alert(i)
//outputs 1
i =0
i--
Alert(i)
//outputs -1

Answer 2

You don't need to. it's just preferred when iterating

Answer 3

These are the post & pre increment (++) , and decrement operator(--) which is mostly used for 'loops' like for, while and dowhile