Introduction to Abstract Data Types (ADT): past paper questions

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• Question 7May/June 2026, paper 21Structured12 marks

  Different data structures will be suitable for different computing applications. Identify a computing application where a queue data structure is suitable.

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• Question 3Oct/Nov 2025, paper 23Structured5 marks

  A program uses a stack to hold up to 30 integer values. The stack is implemented using a global integer variable and a global 1D array.

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• Question 3Oct/Nov 2024, paper 22Structured7 marks

  A program uses a stack to hold up to 60 numeric values. The stack is implemented using two integer variables and a 1D array.

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• Question 3Oct/Nov 2023, paper 21Structured8 marks

  The diagram represents an Abstract Data Type (ADT). The operation of this stack may be summarised as follows: • The TopOfStack pointer points to the last item added to the stack. • The BottomOfStack pointer points to the first item on the stack.

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• Question 4May/June 2026, paper 22Structured9 marks

  4 A desktop web browser stores the history of web addresses visited. The web browser uses a back button and forward button to move between web pages recently visited. Two stacks are used when each of these buttons are clicked: • back stack • forward stack.

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• Question 9Oct/Nov 2025, paper 31Structured9 marks

  A stack has been implemented using pseudocode to store a maximum of 100 string items using the global variables in the following table: Identifier | Data type…

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• Question 3Oct/Nov 2024, paper 23Structured10 marksHas a diagram

  The implementation of a linked list uses an integer variable and a 1D array List of type Node.

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• Question 3Oct/Nov 2023, paper 22Structured9 marks

  The diagram represents a linked list Abstract Data Type (ADT). • Ptr1 is the start pointer. Ptr2 is the free list pointer.

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• Question 6May/June 2026, paper 23Structured13 marksHas a diagram

  A linked list is an example of an Abstract Data Type (ADT). A linked list is implemented using: • a 1D array for the data items • a 1D array for the link pointers • a start pointer. The linked list maintains the data items in alphabetical order.

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• Question 10Oct/Nov 2025, paper 33Structured6 marks

  A stack, StackArray, is to be implemented using pseudocode, to store a maximum of 100 string items in an appropriate array. Declarations are required so that the stack has a beginning, an end and a maximum size. An array is also required to store the data.

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• Question 11Oct/Nov 2024, paper 31Structured12 marksHas a diagram

  The following diagram shows an ordered binary tree. A linked list of nodes is used to store the data. Each node consists of a left pointer, the data and a right pointer.

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• Question 8Oct/Nov 2023, paper 22Structured18 marks

  A class of students are developing a program to send data between computers. Many computers are connected together to form a wired network. Serial ports are used to connect one computer to another.

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• Question 1May/June 2026, paper 41Structured26 marks

  A program stores integer data in a linear queue. The queue is created as a global 1D array with space for 10 elements. The queue has a global head pointer, initialised to –1, that points to the first element in the queue.

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• Question 1Oct/Nov 2025, paper 41Structured20 marks

  A program stores integers in a stack. The stack is represented as a 1D array of 30 elements with the identifier Stack The global pointer TopOfStack stores the index of the last element inserted into the stack.

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• Question 11Oct/Nov 2024, paper 32Structured12 marksHas a diagram

  This binary tree shows an ordered list of integers. A linked list of nodes is used to store the data. Each node consists of a left pointer, the data and a right pointer.

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• Question 3Oct/Nov 2023, paper 23Structured9 marks

  The diagram represents a queue Abstract Data Type (ADT). The organisation of this queue may be summarised as follows: • The FrontOfQueue pointer points to the next data item to be removed. • The EndOfQueue pointer points to the last data item added.

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• Question 3May/June 2026, paper 42Structured27 marks

  A 2D array is used to store the linked list, LinkedList. The linked list stores a maximum of eight data items. Each data item is an integer.

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• Question 2Oct/Nov 2025, paper 43Structured24 marks

  A program reads string data from a text file into a linear queue and then compresses the data. The queue is created using the global 1D array Queue. The queue can store up to 100 elements.

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• Question 3Oct/Nov 2024, paper 41Structured19 marks

  A linked list stores positive integer data in a 2D array. The first dimension of the array stores the integer data. The second dimension of the array stores the pointer to the next node in the linked list.

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• Question 10Oct/Nov 2023, paper 31Structured10 marks

  A stack is to be set up using the information in the table.

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• Question 5May/June 2025, paper 21Structured7 marks

  Stacks and queues are both abstract data types. A stack uses a top-of-stack pointer to indicate the location of the last item added to the stack.

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• Question 2Oct/Nov 2024, paper 42Structured29 marks

  A linear queue data structure is designed using a record structure.

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• Question 9Oct/Nov 2023, paper 32Structured13 marks

  A stack Abstract Data Type (ADT) is to be implemented using pseudocode, with procedures to initialise it and to push new items onto the stack. A 1D array Stack stores the contents of the stack.

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• Question 6May/June 2025, paper 22Structured9 marks

  Two arrays Data and Pointer are accessed by the procedure Place() Data and Pointer are both global arrays of type INTEGER The contents of these two arrays are…

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• Question 2May/June 2025, paper 23Structured11 marks

  A programmer uses a number of Abstract Data Types (ADT) in the programs that she is developing. A stack using memory locations 400 to 409 is used in one program. The diagram represents the current state of the stack.

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• Question 3May/June 2024, paper 21Structured8 marks

  The diagram shows an Abstract Data Type (ADT) representation of a linked list after data items have been added. • PS is the start pointer. • PF is the free list pointer.

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• Question 2Oct/Nov 2023, paper 41Structured29 marks

  A linear queue is implemented using the 1D array, Queue. The index of the first element in the array is 0.

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• Question 12May/June 2025, paper 33Structured7 marks

  An array is an Abstract Data Type (ADT). Identify two other ADTs.

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• Question 3May/June 2024, paper 41Structured17 marks

  A program reads data from the user and stores the data that is valid in a linear queue. The queue is stored as a global 1D array, QueueData, of string values. The array needs space for 20 elements.

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• Question 1Oct/Nov 2023, paper 42Structured27 marks

  A program stores lower-case letters in two stacks. One stack stores vowels (a, e, i, o, u) and one stack stores consonants (letters that are not vowels). Each stack is implemented as a 1D array.

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