Question

JAVA --Design a class named StackOfStrings that contains: a. A private array elements to store strings in the stack b. A private data field size to store the number of strings in the stack c. A constructor to construct an empty stack with a default capacity of 4 d. A constructor to construct an empty stack with a specified capacity e. A method empty() that returns true if the stack is empty f. A method push(String value) that stores value at the top of the stack. This method checks if the stack is full before pushing to it. In case the stack is full, it i. copies the contents of the stack to a new temp array ii. creates a new elements array with double the current capacity iii. copies back temp to elements iv. places value at the top of the new stack g. A method pop() that removes the string at the top of the stack and returns it. In case the stack is empty, it returns "Stack is EMPTY" h. A method peek() that returns the string at the top of the stack without removing it from the stack. In case the stack is empty, it returns "Stack is EMPTY" i. A method printStack() as shown below: public void printStack(){ System.out.print("Stack (top to bottom) : "); for (int i=size‐1; i>‐1; i‐‐) System.out.print(elements[i] + " "); System.out.println(); }1. Draw the UML diagram for the StackOfStrings class. 2. Implement the StackOfStrings class. 3. Use the test program shown on the following page which creates a StackOfStrings object, and then allows the user to push, pop or peek at the stack. 4. Draw the UML diagram for the StackOfStrings object created in the test program. import java.util.Scanner; public class Test { public static void main(String[] args) { StackOfStrings stack = new StackOfStrings(); System.out.println("STACK OF STRINGS\nType PSH followed by a space " + "and a string and a carriage return or\nType POP followed " + "by a carriage return or\nType PEK followed by a carriage " + "return or \nType STP followed buy a carriage return"); Scanner input = new Scanner(System.in); while (true) { System.out.print("Enter command: "); String s = input.nextLine(); String stackCommand = s.substring(0, 3); switch (stackCommand) { case "PSH": stack.push(s.substring(s.indexOf(" ") + 1)); stack.printStack(); break; case "POP": System.out.println(stack.pop()); stack.printStack();break; case "PEK": System.out.println(stack.peek()); stack.printStack(); break; case "STP": System.exit(0) default: System.out.println("Illegal input. Try again."); } } } } class StackOfStrings { // Implement the class here }

Answer 1

public class Queue{
int elements[];
int size;
Queue(){
elements = new int[8];
size = 0;
}
void enqueue(int v){
elements[size++] = v;
if(size == elements.length){
doubleSize();
}
}
int dequeue(){
int temp = -1;
if(empty()) System.out.println("Queue is empty");
else{
temp = elements[0];
shiftLeft();
size--;
}
return temp;
}
boolean empty(){
if(size == 0) return true;
else return false;
}
int getSize(){
return size;
}
private void doubleSize(){
int temp[] = elements;
elements = new int[size * 2];
for(int i = 0; i < temp.length; i++){
elements[i] = temp[i];
}
}
private void shiftLeft(){
for(int i = 0; i < size - 1; i++){
elements[i] = elements[i + 1];
}
}
}