A Level Programming Concepts

Which of the following pseudocode snippets correctly calculates the total of all even numbers within a range entered by the user?

• low = input ("Enter the first number in the range") high = input ("Enter the last number in the range") total = 0 for n = low to high -1 if n MOD 2 == 0 then total = total + n endif next n print("Total of even numbers in the range ",total)

• low = input ("Enter the first number in the range") high = input ("Enter the last number in the range") total = 0 for n = low to high if n MOD 2 == 1 then total = total + n endif next n print("Total of even numbers in the range ",total)

• low = input ("Enter the first number in the range") high = input ("Enter the last number in the range") total = 0 for n = low to high -1 if n MOD 2 == 1 then total = total + n endif next n print("Total of even numbers in the range ",total)

• low = input ("Enter the first number in the range") high = input ("Enter the last number in the range") total = 0 for n = low to high if n MOD 2 == 0 then total = total + n endif next n print("Total of even numbers in the range ",total)

Which of the following is NOT a way to make programs easy to understand and maintain?

• Meaningful variable names

• Comments to explain sections of the program

• Modular structure

• Using complex and obscure variable names

What is the output of the subroutine answerYorN if the user inputs "y"?

• "Please enter y or n: "

• "You must answer y or n"

• "y"

• "n"

What does the subroutine answerYorN do if the user inputs an invalid response?

• It terminates the program.

• It prints "You must answer y or n" and asks for input again.

• It returns the invalid response.

• It skips the input and continues.

What is the purpose of the subroutine answerYorN?

• To calculate the average temperature.

• To validate user input as either "y" or "n".

• To find the highest temperature.

• To complete the trace table.

Explain the difference between passing parameters by value and by reference.

• By value: The value is copied into a variable in the subroutine; By reference: The address is passed to the subroutine.

• By value: The address is passed to the subroutine; By reference: The value is copied into a variable in the subroutine.

• By value: The value is copied into a variable in the subroutine; By reference: The value is copied into a variable in the subroutine.

• By value: The address is passed to the subroutine; By reference: The address is copied into a variable in the subroutine.

What is meant by modular programming?

• Combining multiple programs into one large program.

• Splitting a large program up into self-contained subroutines (modules).

• Writing a program without using any subroutines.

• Using only global variables in a program.

Give four advantages of modular programming.

• Easier to debug and maintain, independent testing, reusability, team collaboration.

• Harder to debug and maintain, independent testing, reusability, team collaboration.

• Easier to debug and maintain, dependent testing, reusability, team collaboration.

• Easier to debug and maintain, independent testing, reusability, individual work.

Explain why using local variables makes a large program easier to maintain.

• It keeps each module dependent on all other modules.

• It keeps each module independent of all other modules.

• It makes the program run faster.

• It increases the complexity of the program.

Give three essential properties of a recursive routine.

• Stopping condition, infinite calls, no base case.

• No stopping condition, finite calls, base case.

• Stopping condition, base case, finite number of calls.

• No stopping condition, infinite calls, base case.