do in java please

Q$1-$ Coding

Write the prefix expression that represents the following infix expression

$(\frac{a}{b})*c-(d+e)*f$

Write the following prefix expression as an infix expression

$--\frac{a}{b}+c^{*}$def

Write an algorithm to evaluate prefix expressions $($pseudocode is on page $417$ of

textbook$)$

Q$3-$ Discussion

Show a stack trace for your algorithm with an example of which prefix expression you used. $//$ Returns the value of a given prefix expression.

$//$ Precondition: str is a string containing a valid prefix expression with no

$//$ blanks.

evaluatePrefix$($str: string$)$: real

$\{$

strLength $=$ the length of $str$

if $($strLength $==1)$

return the value of the single$-$letter operand in str $//$ Base case

e$1$se

$\{$

$op=$strcharAt$(0)\frac{\frac{?}{?}}{?}$str begins with an operator

$//$ Find the end of the first prefix expression, that is$,$ the first operand

endFirst $=$ endPre$($str$,1$