Questions and Answers
What is the primary characteristic of a stack data structure?
In a stack, where do addition and deletion of elements occur?
Which of the following is an example of a stack application?
How can a stack be implemented in C++?
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What is the primary advantage of using a linked list to implement a stack?
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What is the purpose of the undo operation in text editors, which is implemented using a stack?
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In a stack-based implementation, which operation is typically more efficient?
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What is the primary advantage of using a stack to remove recursion?
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What is the time complexity of removing an element from the head of a linked list-based stack?
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Which of the following is a characteristic of a linked list-based stack implementation?
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What is the purpose of the initializeStack function in a linked list-based stack implementation?
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What is the purpose of the push function in a linked list-based stack implementation?
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Which of the following is a benefit of using a linked list-based stack implementation?
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What is the purpose of the pop function in a linked list-based stack implementation?
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What is the time complexity of pushing an element onto a linked list-based stack?
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What is the purpose of the top function in a linked list-based stack implementation?
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What is the purpose of the isFullStack function in a linked list-based stack implementation?
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What is the primary purpose of the isFullStack operation in a stack?
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What is a characteristic of a dynamic stack implemented as a linked list?
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Which of the following is an application of stacks?
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What is the purpose of the stackTop variable in an array-based stack implementation?
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What is the precondition for the pop operation in a stack?
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What is the purpose of the initializeStack operation in a stack?
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What is the primary purpose of the top operation in a stack?
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What is the benefit of using a linked list to implement a stack?
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What is the primary purpose of the push operation in a stack?
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What is the purpose of the isEmptyStack operation in a stack?
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What is the purpose of the stackADT class in a stack implementation?
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Study Notes
Stack Concept
- A stack is a data structure similar to arrays and linked lists, holding a sequence of elements.
- It follows the Last-In, First-Out (LIFO) principle, meaning addition and deletion of elements occur only at one end, called the top.
Real-Life Examples of Stacks
- A bookshelf is a real-life example of a stack, where you need to remove the first book to access the one behind it.
Stack Applications
- Evaluating balanced symbols in compilers to check for syntax errors.
- Undo operation in text editors, where all text changes are stored in a stack.
- Parsing arithmetic expressions, such as ((24-6/3)(3*5+8/4))-(2+3).
Stack Abstract Data Type (ADT)
- The class stackADT defines stack operations as an Abstract Data Type (ADT).
- It includes operations such as push, top, pop, isFullStack, isEmptyStack, and initializeStack.
Stack Operations
- Push: adds a new element onto the stack, with a precondition that the stack must exist and not be full.
- Top: retrieves the top element of the stack without removing it, with a precondition that the stack must exist and not be empty.
- Pop: removes the top element from the stack, with a precondition that the stack must exist and not be empty.
- IsFullStack: checks if the stack is full and returns true or false.
- IsEmptyStack: checks if the stack is empty and returns true or false.
- InitializeStack: initializes the stack to an empty state.
Implementing Stack ADT
- A stack can be implemented as either an array or a linked list structure.
- Stacks implemented as arrays are static, having a fixed size, while those implemented as linked lists are dynamic, growing in size as needed.
Implementing Stack using Array
- The first stack element is put in the first array slot, the second in the second slot, and so on.
- The top of the stack is accessed through the index of the last element added to the stack.
- A variable (stackTop) is used to keep track of the top position of the array.
Implementing Stack using Linked List
- A linked list implementation of a stack is more efficient for inserting and removing elements at the head.
- The default constructor initializes the stack to an empty state by setting stackTop to NULL.
- The stack is never full, as memory is allocated and deallocated dynamically.
- The isFullStack function always returns false.
Stack Operations using Linked List
- Push: adds a new element at the beginning of the linked list, updating the stackTop pointer.
- Pop: removes the top element of the stack, updating the stackTop pointer.
- Top: returns the information of the node pointed to by stackTop.
Removing Recursion
- A stack can be used to design a non-recursive algorithm to print a linked list backward.
- A non-recursive algorithm can be used to print a linked list backward using a stack.
STL Class Stack
- The Standard Template Library (STL) provides a class to implement a stack in a program.
- The STL class stack is similar to the implementation described in the Textbook.
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Description
Learn about stacks and their operations, including implementation as an array and linked list. Part of the Data Structures and Algorithms course, Semester 2, 2023/2024.