Question

"In computer science, an abstract data type (ADT) is a mathematical model for data types where a data type is defined by its behavior (semantics) from the point of view of a user of the data, specifically in terms of possible values, possible operations on data of this type, and the behavior of these operations." (Source: "Abstract Data Types." Wikipedia. Wikimedia Foundation, 2 Nov. 2016. Web. 9 Nov 2016. < https: //en.wikipedia.org/wiki/Abstract data type > .) A stack is an example of an abstract data type (ADT). A. Create a Power Point Presentation (> = 6 slides) Research the basic concept of a stack and explain it in your presentation. Illustrate the concept with two reallife examples. Cite your sources. Implementation of the ADT Implement the stack ADT in a Stack class. The stack will hold integers (ints). For the implementation, use a fixed size array (not the ArrayList class). Implement the following methods: 1. the no-arg constructor initializes a stack with a default capacity of 4, i.e. the stack can take 4-elements at most), 2. a constructor that initializes a stack with a specific capacity (given as parameter), 3. push (adds a new element to the stack if it is not full), 4. pop (removes the last element from a stack if it is not empty), 5. peek (if the stack is not empty, returns the value of the last element from a stack, but does not remove the element from the stack), 6. getSize (returns how many elements are currently in the stack), 7. getCapacity (returns the capacity of the stack), 8. isFull (returns true if the stack is full), 9. isEmpty (returns true if the stack is empty). 10. toString (returns a string of all the elements). Optional (for bonus points): 11. equals (compares the stack with another stack given as parameter and returns true if both are of equal capacity and have the same elements in the same positions), 12. a constructor that copies another stack given as parameter, B. Design the Stack class using a UML diagram. C. Implement the Stack class in Java. D. Test all the methods of your ADT in a separate demo/test program. It is recommended to test each method right after it's implementation (to make sure it is working correctly), before moving on to the next one.

Part A is done, I do not know how to start these steps..

Answer 1

Please find below the solution:

I have covered the bonus section also:

//StackClass.java

import java.util.NoSuchElementException;

public class StackClass {

//instance variables

int topElement,capacity,currentSize;

int stackArray[] = new int[capacity];

//constructor that takes capacity

public StackClass(int capacity)

{

this.capacity=capacity;

topElement=-1;

currentSize=0;

stackArray = new int[capacity];

}

//constructor without parameter

public StackClass()

{

this.capacity=4;

topElement=-1;

currentSize=0;

stackArray = new int[capacity];

}

//push function

public void push(int n)

{

if(isFull())

throw new StackOverflowError("Stack already full");

stackArray[currentSize]=n;

topElement++;

currentSize++;

}

//empty function

public boolean isEmpty()

{

return currentSize==0;

}

public int pop()

{

if(isEmpty())

throw new NoSuchElementException("Stack under flow");

int n= stackArray[topElement];

topElement--;

currentSize--;

return n;

}

//it will return the top element

public int peek()

{

if(isEmpty())

throw new NoSuchElementException("Stack under flow");

return stackArray[topElement];

}

//it will return the capacity

public int getCapacity()

{

return this.capacity;

}

//it will return the size

public int getSize()

{

return this.currentSize;

}

//check if array is full or not

public boolean isFull()

{

return currentSize==capacity;

}

//toString function

public String toString()

{

StringBuffer s = new StringBuffer();

if(isEmpty())

s.append("Empty Stack\n");

else{

int j=topElement;

for(j=topElement;j>=0;j--)

{

s.append(stackArray[j]+"\n");

}

}

return "Current elements in Stack \n"+s;

}

//this is the bonus section

//i have implemeneted

//check for two stack eqaulity

public boolean equals(StackClass anotherStack)

{

boolean flag = true;

if(this.getCapacity()!=anotherStack.getCapacity())

return false;

if(this.getSize()!=anotherStack.getSize())

return false;

int index=0;

int t1[]=new int[this.getSize()];

int t2[]=new int[anotherStack.getSize()];

while(!this.isEmpty())

{

t1[index]=this.pop();

t2[index]=anotherStack.pop();

index++;

}

for(int i=0;i<t1.length;i++)

{

if(t1[i]!=t2[i])

{

flag=false;

break;

}

}

for(int l=t1.length-1;l>=0;l--)

{

this.push(t1[l]);

anotherStack.push(t2[l]);

}

return flag;

}

//copy the stack to another stack

public StackClass(StackClass another)

{

this.stackArray=new int[another.getCapacity()];

this.topElement=-1;

this.currentSize=0;

this.capacity=another.capacity;

int a[] = new int[stackArray.length];

for(int i=0;i<a.length;i++)

{

a[i]=another.pop();

}

for(int j=a.length-1;j>=0;j--)

{

this.push(a[j]);

another.push(a[j]);

}

}

}

//TestStack.java

public class TestStack {

public static void main(String[] args) {

//created a stack

StackClass stack = new StackClass();

//pushed some values

stack.push(34);

stack.push(23);

stack.push(90);

stack.push(12);

//created one more stack by using constructor

StackClass another = new StackClass(stack);

//checking for equality of

//it should return true

//because another is created using copy constructor

System.out.println("Is stack equal to another stack : "+stack.equals(another));

//getting the peek element

System.out.println("Stack peek element : "+stack.peek());

System.out.println("another Stack peek element : "+another.peek());

System.out.println("Is stack full : "+ stack.isFull());

System.out.println("Removing the top element from stack : "+stack.pop());

System.out.println("Checking the top element after removing : "+ stack.peek());

System.out.println("Capacity of stack : "+another.getCapacity());

//it will call toString method:

System.out.println(stack);

}

}

OUTPUT:

Is stack equal to another stack: true Stack peek element: 12 another Stack peek element12 Is stack full true Removing the top element from stack12 Checking the top element after removing: 90 Capacity of stack: 4 Current elements in Stack 90 34

UML diagram:

Stack clas tor lcment t MLー 0 Shack Sn s Smphy: boolean isfu)boslcan

Please do let me know if u have any doubts...