Explain with examples: $(a)$ Complete,$(b)$ Condensed,and $(c)$ Bond-line structural formulas.

(N/A) Complete structural formula (dash formula):
$(i)$ The covalent bond is represented by a dash $(-)$ or a small line.
$(ii)$ In the structure,every dash $(-)$ represents one bonding electron pair or two bonding electrons.
$(iii)$ $A$ single dash $(-)$ represents a single bond.
$(iv)$ $A$ double bond is represented by a double dash $(=)$.
$(v)$ $A$ triple bond is represented by a triple dash $(\equiv)$.
$(vi)$ Lone pairs of electrons on heteroatoms (e.g.,$O, N, S, X$ etc.) may or may not be shown.
$(vii)$ Every two atoms are connected by a dash $(-)$ to obtain the complete structure.
Example: Ethane $(CH_3-CH_3)$,Ethene $(CH_2=CH_2)$,Ethyne $(CH\equiv CH)$.
$(b)$ Condensed structural formula:
These structural formulas can be further abbreviated by omitting some or all of the dashes representing covalent bonds and by indicating the number of identical groups attached to an atom by a subscript.
$(i)$ In the structure,all single bonds indicated by dashes are not written.
$(ii)$ These formulas can be condensed by enclosing the repetitive structural unit within a bracket and placing an integer as a subscript indicating the number of times the structural unit is repeated.
$(iii)$ The multiple bonds present between $C$ and heteroatoms are also not written.
Example: $CH_3COCH_3$ is written instead of $CH_3-CO-CH_3$.
Example: The condensed structure of $CH_3-CH_2-CH_2-CH_2-CH_2-CH_2-CH_2-CH_3$ is written as $CH_3(CH_2)_6CH_3$.
$(c)$ Bond-line structural formula:
In this representation,carbon and hydrogen atoms are not shown,and the chain of carbon-carbon bonds is drawn as a zigzag line. The terminals of the line represent methyl groups $(CH_3)$,and the intersections represent methylene $(CH_2)$ or methine $(CH)$ groups. Heteroatoms are explicitly written.