Chapter 8 : Review Question

Q6 : What is unusual about Python’s design of compound statements?

A : Python uses indentation to specify compound statements. For example,

if x > y :

x = y

print “case 1″

equally indent statements are grouped as one compound statement.

Q7 : Under what circumstances must an F# selector have an else clause?

A : If the expression returns a value, it must have an else clause.

Q8 : What are the common solutions to the nesting problem for two-way selectors?

A : The common solution is to force an alternative semantics, by using compound statements.

Q9 : What are the design issues for multiple-selection statements?

A :

-What is the form and type of the control statement?

-How are the selectable segments specified?

-Is execution flow through the structure restricted to include just a single selectable segment?

-How are case values specified?

-What is done about unrepresented expression values?

Q10 : Between what two language characteristics is a trade-off made when deciding whether more than one selectable segment is executed in one execution of a multiple selection statement?

A : In Ada, the choice lists of the case statement must be exhaustive, so that there can be no unrepresented values in the control expression. In C++, unrepresented values can be caught at run time with the default selector. If there is no default, an unrepresented value causes the whole statement to be skipped.