Question

Could somebody please help.!

Please DON't copy paste from other places and please read the question and answer exactly what's asked.

Thank you I much appreciate it.

You are to write a program name MyArrayStack.java that create/build the ArrayStack data structure. The class must be written to accept any type of Objects. The following must be implemented i.e. YOU must write the code (do not import any stack from the Java Library): 1. One default constructor that will create an MyArrayStack object with a default size (capacity) of 10 ------ public MyArrayStack (); 2. Another constructor that accepts a parameter of type int and sets the size to this parameter ---- public MyArrayStack(int n); 3. A method that allows you to push a new object in MyArrayStack ---- public Boolean push(Object x); 4. A method that allows you to delete the object from MyArrayStack ---- public Object pop(); 5. A method that allows you to access the object in the top of MyArrayStack ---- public Object peek(); 6. A method would test to see if the MyArrayStack is empty ---- public boolean isEmpty(); Now, write a driver program TestStack.java, which has two method: 1. public static void main(String[] args); 2. public boolean TestL(String S);

Answer 1

// MyArrayStack.java

public class MyArrayStack {
  
   private Object arr[];
   private int top;
  
   // default constructor
   public MyArrayStack()
   {
       arr = new Object[10];
       top = -1;
   }
  
   // parameterized constructor
   public MyArrayStack(int n)
   {
       arr = new Object[n];
       top = -1;
   }
  
   // method to push an object at top of stack
   public boolean push(Object x)
   {
       if(top < (arr.length-1))
       {
           top++;
           arr[top] = x;
           return true;
       }
      
       return false;
   }
  
   //method to remove and return the element at top of stack
   public Object pop()
   {
       if(!isEmpty())
       {
           Object obj = arr[top];
           top--;
           return obj;
       }
      
       return null;
   }
  
   // method to return the top element of stack
   public Object peek()
   {
       if(!isEmpty())
       {
           return arr[top];
       }
      
       return null;
   }
  
   // method to return true of stack is empty , else false
   public boolean isEmpty()
   {
       return(top == -1);
   }  
}

//end of MyArrayStack.java

// TestStack.java

import java.util.Scanner;

public class TestStack {
  
   // method to return true if S belongs to the given language else false
   public boolean TestL(String S)
   {
       // create an array of size of the length of the String S
       MyArrayStack stack = new MyArrayStack(S.length());
       int i=0;
       // loop over the string until "$" is encountered, pushing the characters into the stack
       while((i < S.length()) && (S.charAt(i) != '$'))
       {
           stack.push(new Character(S.charAt(i)));
           i++;
       }
      
       i++; // ignore $
      
       // loop over the remaining string, comparing the characters of the string with the character in the stack
       while( i < S.length())
       {
           // if stack is empty, then return false
           if(stack.isEmpty())
               return false;
           else if(!stack.peek().equals(new Character(S.charAt(i)))) // if current character of the string doesn't match the character at top of stack, return false
               return false;
           stack.pop(); // if characters match, remove the character from stack and analyse the next character in the string
           i++;
       }
      
       // after analysing all the characters in the string, if stack is not empty, return false
       if(!stack.isEmpty())
           return false;
      
       return true; // S belongs to the language
   }

   public static void main(String[] args)
   {
       String S;
       Scanner scan = new Scanner(System.in);
       // input of string
       System.out.print("Enter an input string: ");
       S = scan.nextLine();
       TestStack ts = new TestStack(); // create an object of TestStack
// test if S is in language or not
       if(ts.TestL(S))
           System.out.println(S+" is in the given language");
       else
           System.out.println(S+" is not in the given language");
       scan.close();
   }
}

//end of TestStack.java

Output:

Enter an input string: madam$madam madam$madam is in the given language

Enter an input string: race$eca race$eca is not in the given language