Control Structure

Question 1

What are the conditional statements available in Ruby?

Answer 1

1) if
2) Case
3) unless

Question 2

How we can use if condition?

Answer 2

If conditon can be used in threee variants
if
end

if
else
end

if
elsif
else
end

Question 3

What is very popular one line condtitional statement?

Answer 3

tenary operator

condition ? true : false

Question 4

Can case statements be assigned to any variable?

Answer 4

yes. This value can be assigned to a variable preceding the case statement.

happy = case

when …

end

Question 5

What is the alternative way of expressing ‘if not’.?

Answer 5

unless

Question 6

What the looping structures available in Ruby?

Answer 6

for,until,while,loop

Question 7

Is each a loop?

Answer 7

no, its an iterator.Also it can be used as built in methods in classes like array,hash

Question 8

How we can use for loop?

Answer 8

It can be used in three different ways.

for i in 1..10
end

for i in 1..10 do
end

single line

for i in 1..10 do end - do is mandatory

Question 9

give the while loop alternate syntax?

Answer 9

i = 0
begin
	puts(arr[i])
	i += 1
end while i < arr.length

Question 10

give the until loop alternate syntax?

Answer 10

i = 0
until i == arr.length 
	puts(arr[i])
	i +=1
end

Question 11

How “loop” keywords can be used in Ruby?

Answer 11

loop do

end

loop {

}

Question 12

What is a statement modifier?

Answer 12

A condition which follows a statement such as with x = 1 if a == true

Question 13

Does the case statement in Ruby have fall-through behavior?

Answer 13

No. Fall through means , control moves to the matching case, and then execution continues (“falls through”) to the statements associated with the next case. fallthrough is usually prevented with a break keyword at the end of the matching body

Question 14

What are some advantages of a case statement versus repeated elsif statements?

Answer 14

It shows intent. It DRY’s out the condition.

Question 15

Why might you use #each instead of for/in?

Answer 15

It’s the “Ruby way” - an example of how Ruby defines methods that mimic natural language concepts. Iterator methods such as #each read more naturally. #each is a block so it defines a new variable scope. for/in depends on the existence of #each which implies that #each is a more fundamental aspect of the language.