Nested if blocks in pseudocode

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Quick Questions

Shade in the A or B circle for each question.

1. In a nested if, when is the inner condition checked?

A Only when the outer condition is true

B Every time, whether the outer condition is true or not

2. Which pseudocode shows the inner block indented correctly?

A if age >= 12 then if hasTicket = true then print "Enter" end if end if

B if age >= 12 then if hasTicket = true then print "Enter" end if end if

3. A nested if has 2 if blocks, one inside the other. How many end if lines does it need?

A 2, one for each if

B 1, because they are joined together

4. Which is the correct order for closing a nested if?

A Close the outer if first, then the inner if

B Close the inner if first, then the outer if

5. score = 40. Outer if: score >= 50. Inner if: score = 100. What happens to the inner if?

A It is skipped, because the outer condition is false

B It is checked, and found to be false

Match the Pairs

Draw a line connecting each item on the left to its match on the right.

Left column		Right column
1if age >= 12 then if hasTicket = true then		ANo indenting, so it is hard to see that the second if is nested inside the first.
2 end if end if		BEach if block gets its own end if. The inner one closes first, then the outer one
3The inner block is indented so you can see which if it belongs to		Cif raining = true then if haveUmbrella = true then print "Take umbrella" end if end if
4A nested if can do the same job as AND, because both conditions must be true for the action to run		DThe outer if has no end if. Every if, including the outer one, needs its own end if.
5if age >= 12 then if hasTicket = true then print "Enter" end if		EA nested if: the inner if is written inside the outer if, so hasTicket is only checked when age >= 12 is true
6if temp > 30 then if humid = true then print "Stay inside" end if end if		Fif score > 50 then if score > 90 then print "Top mark" end if end if

Definitions

nested if

Fill in the Blanks

Complete each line of code by filling in the missing parts.

if age >= 12 then __ tall = true then print "Ride" end if end if

if age >= 12 then if tall = true then print "Ride" end if ______

if score __ 50 then if score >= 80 then print "Merit" end if end if

if age >= 12 ___ tall = true then print "Ride" end if

if raining = true then if windy = true ____ print "Coat" end if end if

Spot the Error

Shade in the letter of the line that contains an error.

Question 1

A if age >= 12 then

B if has_ticket = true

C print "Enter"

D end if

E end if

Question 2

A if score >= 50 then

B if score >= 90 than

C print "Excellent"

D end if

E end if

Question 3

A if temp > 30 then

B print "Hot day"

C if humidity => 70 then

D print "Muggy"

E end if

F end if

Question 4

A if logged_in = true then

B if is_admin = true then

C say "Admin panel"

D end if

E end if

Question 5

A if temp > 25 then

B print "Warm"

C if temp > 35 then

D print "Very hot

E end if

F end if

Answer Key

Nested if blocks in pseudocode

Section A: Quick Questions

A — Only when the outer condition is true

B — if age >= 12 then if hasTicket = true then print "Enter" end if end if

A — 2, one for each if

B — Close the inner if first, then the outer if

A — It is skipped, because the outer condition is false

Section B: Match the Pairs

if age >= 12 then if hasTicket = true then → A nested if: the inner if is written inside the outer if, so hasTicket is only checked when age >= 12 is true

end if end if → Each if block gets its own end if. The inner one closes first, then the outer one

The inner block is indented so you can see which if it belongs to → if score > 50 then if score > 90 then print "Top mark" end if end if

A nested if can do the same job as AND, because both conditions must be true for the action to run → if raining = true then if haveUmbrella = true then print "Take umbrella" end if end if

if age >= 12 then if hasTicket = true then print "Enter" end if → The outer if has no end if. Every if, including the outer one, needs its own end if.

if temp > 30 then if humid = true then print "Stay inside" end if end if → No indenting, so it is hard to see that the second if is nested inside the first.

Section C: Definitions

nested if — An if block written inside another if block. The inner condition is only checked when the outer condition is true. Indent the inner block and give each if its own end if.

Section D: Fill in the Blanks

if age >= 12 then
    if tall = true then print "Ride" end if
end if

if age >= 12 then
    if tall = true then print "Ride" end if
end if

if score >= 50 then
    if score >= 80 then print "Merit" end if
end if

if age >= 12 and tall = true then
    print "Ride"
end if

if raining = true then
    if windy = true then print "Coat" end if
end if

Section E: Spot the Error

B — The inner if is missing the keyword then. It should be: if has_ticket = true then

B — The inner if ends with the wrong word. The keyword is then, not than. It should be: if score >= 90 then

C — The comparison operator => is not valid. 'Greater than' is > (or >= for 'greater than or equal to'). It should be: if humidity > 70 then

C — say is not a pseudocode keyword. Output is written with print. It should be: print "Admin panel"

D — The text being printed is missing its closing quote. It should be: print "Very hot"