Selection: making decisions in programs

9.Match each language to the keyword it uses for else-if chaining.

10.In a switch statement, if no case matches, a default action is always executed.

11.Consider the pseudocode: if x > 0 then if x > 10 then print "large" else print "small" else print "negative". If x = 5, what is printed?

12.Arrange the steps to correctly evaluate an if-else-if chain.

13.What is the general syntax of an if-then-else statement in pseudocode?

14.In the Guarded Command Language (GCL), exactly one of the statements whose guard is true is evaluated, but which one is arbitrary.

15.Which of the following is an example of a conditional expression that evaluates to a value without changing control flow?

16.The else clause is mandatory in an if-then-else statement.

17.In the pseudocode: if discount == 10 then print "you have to pay $30" else if discount == 20 then print "you have to pay $20" else print "you have to pay $10". If discount = 10, which statements are executed?

18.Which of the following is NOT a way to implement a switch statement if a language does not have one?

19.In ALGOL 68, the keyword 'elif' was standardized in the 1973 Revised Report.

20.What is the main advantage of using 'else if' instead of nested 'else' followed by 'if'?

21.Match the term to its description.

22.What is the purpose of an 'if' statement in a program?

23.The 'else' clause is optional in an if-then-else statement.

24.Which of the following are comparison operators commonly used in conditions? (Select all that apply)

25.In the pseudocode: if x > 5 then print "big" else if x > 0 then print "small" else print "negative". If x = 3, what is printed?

26.Which of the following is a recommended way to avoid the dangling else problem in many programming languages?

27.A program checks the temperature of a room. If the temperature is above 25°C, it turns on the air conditioning. Which part of the if-then-else statement is the condition?

28.A student writes: if score ≥ 50 then print "Pass" else print "Fail". What is the output if score = 50?

29.In an if-then-else statement, if the condition is false, the statements in the else block are executed.

30.A program uses the following pseudocode to assign a grade based on a score: if score ≥ 90 then grade = 'A' else if score ≥ 80 then grade = 'B' else if score ≥ 70 then grade = 'C' else grade = 'D'. What is the grade if score = 85?

31.A program uses the following pseudocode: if x > 0 then if x > 10 then print "large" else print "small" else print "negative". What is printed if x = 5?

32.Which of the following best describes the purpose of the 'else' clause in an if-then-else statement?

33.In an if-then-else statement, the 'else' clause is mandatory.

34.What is the output of the following pseudocode if x = 7? if x > 10 then print "large" else if x > 5 then print "medium" else print "small" end if

35.A program uses the following nested if statement: if x > 0 then if x > 10 then print "big" else print "small" end if else print "negative" end if What is printed if x = 5?

36.Match each programming language to the keyword it uses for else-if chaining.

37.Arrange the steps to correctly evaluate an if-else-if chain in pseudocode.

38.In the Guarded Command Language (GCL), if multiple guards are true, which statement is executed?

39.A conditional statement uses a Boolean expression to decide which part of the program to run.

40.In pseudocode, which keyword is used to chain conditions without increasing indentation in Python?

41.Complete the sentence.

42.What is the name of the construct that supports multiway branching by comparing an expression with constant values?

43.In a program, a variable 'score' is set to 75. The code is: if score ≥ 70 then grade = 'A' else if score ≥ 60 then grade = 'B' else grade = 'C'. What is the value of grade? (Assume grade is a string, answer as the letter)

44.What is the keyword used in Visual Basic for else-if chaining?

45.A program uses the following code: if x mod 2 == 0 then print "even" else print "odd". If x = 7, what is printed? (Answer as 1 for even, 0 for odd)

46.Complete the sentence: In many programming languages, the ___ statement is used when you need to compare a single expression against multiple constant values.

47.Name the two possible values of a Boolean expression.

48.In the pseudocode: if discount == 10 then print "pay $30" else if discount == 20 then print "pay $20" else print "pay $10". If discount = 20, what amount is printed? (Give the numeric value in dollars)

49.What is the term for the problem where an 'else' clause can be ambiguously paired with one of several nested 'if' statements?

50.A shop offers discounts based on the price of an item. The pseudocode is: if price > 100 then discount = 20 else if price > 50 then discount = 10 else discount = 5. What is the discount (in pounds) for an item priced at £75?

51.Fill in the blank:

52.What are the two possible values of a Boolean expression?

53.Explain why using 'goto' statements in early if-then-else constructs led to 'spaghetti code', and how structured programming solves this.

54.Describe the difference between a conditional statement and a conditional expression, giving an example of each.

55.Describe the dangling else problem and explain one way that programming languages resolve it.

56.In a program, a variable 'score' is set to 75. The code is: if score ≥ 70 then grade = 'A' else if score ≥ 60 then grade = 'B' else grade = 'C'. What is the value of grade? (Assume grade is a string, answer as the letter)

57.A program uses the following code: if x mod 2 == 0 then print "even" else print "odd". If x = 7, what is printed? (Answer as 1 for even, 0 for odd)

58.In the pseudocode: if discount == 10 then print "pay $30" else if discount == 20 then print "pay $20" else print "pay $10". If discount = 20, what amount is printed? (Give the numeric value in dollars)

59.A shop offers discounts based on the price of an item. The pseudocode is: if price > 100 then discount = 20 else if price > 50 then discount = 10 else discount = 5. What is the discount (in pounds) for an item priced at £75?