$st[0] = { \{10 , "Bombay"\}} $
$st[1] = { \{11 , "Computer"\}}$
$st[2] = { \{12 , "Science"\}}$
$st[3] = {\{13 , "Engineering"\}}$
$st[4] = {\{14 , "GateCS"\}}$
$st[5] = {\{15 , "2018"\}}$
$e++->ch$ will give $st[0].ch$ $\rightarrow$ $Bombay$
$e$ is incremented, now it will point to $st[1]$
$++e$ $\rightarrow$ $e$ is incremented, now it will point to $st[2]$
$++e->ch$ : it will print $cience$
Reason:
$->$ has higher precedence then $++$, so $->$ will be executed first
$e->ch$ will be executed first and will give $Science$
$++(Science)$: move 1 position to the right and point to c and will give output $cience$
$++e++->ch$ will $ience$
$Reason:$
$->$ has higher precedence then $++$, so $->$ will be executed first
$e++->ch$ will give means $cience$
$++(cience)$ will be incremented and it will be pointing to $i$ and will give $ience$
$e$ is incremented, now it will point to $st[3]$
$e[0].a$ will give $st[3].a$ $\rightarrow$ $13$
$++e->ch$ will give $ngineering$
$Reason:$
$->$ has higher precedence then $++$, so $->$ will be executed first
$e->ch$ will give $Engineering$
$++e->ch$ it is increment will point to $n$ of $Engineering$