Write the structure formulas for the following:
(i) cis-Oct-`3`-ene
(ii) `2,4`-Dimethylpent-`2`-ene
(iii) `3,4`-Dimethylcyclopentene
(iv) `1,3`-Dimethylcyclohexene
(v) Vinylcyclopentane
Strategy: first write down the parent `C` chain. Then introduce the double bond between the suitable `C` atoms. Finally attach the substituents and the suitable number of `H` atoms to satisfy the valency of `C's`. In cycloalkenes, one can write down the double bonds anywhere in the ring but the position of substituents is fixed by the position of double bonds.

Explanation

(i)
(ii)
(iii)
(iv)
(v)