I need a help in my method equalStack in my class StackClass.
Code:
public class StackClass
{
private int maxStackSize; //variable to store the maximum
//stack size
private int stackTop; //variable to point to the top
//of the stack
private DataElement[] list; //array of reference variables
//default constructor
//Create an array of size 100 to implement the stack.
//Postcondition: The variable list contains the base
// address of the array, stackTop = 0, and
// maxStackSize = 100.
public StackClass()
{
maxStackSize = 100;
stackTop = 0; //set stackTop to 0
list = new DataElement[maxStackSize]; //create the array
}//end default constructor
//constructor with a parameter
//Create an array of size stackSize to implement the stack.
//Postcondition: The variable list contains the base
// address of the array, stackTop = 0, and
// maxStackSize = stackSize.
public StackClass(int stackSize)
{
if(stackSize <= 0)
{
System.err.println("The size of the array to implement "
+ "the stack must be positive.");
System.err.println("Creating an array of size 100.");
maxStackSize = 100;
}
else
maxStackSize = stackSize; //set the stack size to
//the value specified by
//the parameter stackSize
stackTop = 0; //set stackTop to 0
list = new DataElement[maxStackSize]; //create the array
}//end constructor
//Method to initialize the stack to an empty state.
//Postcondition: stackTop = 0
public void initializeStack()
{
for(int i = 0; i < stackTop; i++)
list[i] = null;
stackTop = 0;
}//end initializeStack
//Method to determine whether the stack is empty.
//Postcondition: Returns true if the stack is empty;
// otherwise, returns false.
public boolean isEmptyStack()
{
return (stackTop == 0);
}//end isEmptyStack
//Method to determine whether the stack is full.
//Postcondition: Returns true if the stack is full;
// otherwise, returns false.
public boolean isFullStack()
{
return (stackTop == maxStackSize);
}//end isFullStack
//Method to add newItem to the stack.
//Precondition: The stack exists and is not full.
//Postcondition: The stack is changed and newItem
// is added to the top of stack.
// If the stack is full, the method throws
// StackOverflowException
public void push(DataElement newItem) throws StackOverflowException
{
if(isFullStack())
throw new StackOverflowException();
list[stackTop] = newItem.getCopy(); //add newItem at the
//top of the stack
stackTop++; //increment stackTop
}//end push
//Method to return the top element of the stack.
//Precondition: The stack exists and is not empty.
//Postcondition: If the stack is empty, the method throws
// StackUnderflowException; otherwise, a
// reference to a copy of the top element
// of the stack is returned.
public DataElement top() throws StackUnderflowException
{
if(isEmptyStack())
throw new StackUnderflowException();
DataElement temp = list[stackTop - 1].getCopy();
return temp;
}//end top
//Method to remove the top element of the stack.
//Precondition: The stack exists and is not empty.
//Postcondition: The stack is changed and the top
// element is removed from the stack.
// If the stack is empty, the method throws
// StackUnderflowException
public void pop() throws StackUnderflowException
{
if(isEmptyStack())
throw new StackUnderflowException();
stackTop--; //decrement stackTop
list[stackTop] = null;
}//end pop
//Method to make a copy of otherStack.
//This method is used only to implement the methods
//copyStack and copy constructor
//Postcondition: A copy of otherStack is created and
// assigned to this stack.
private void copy(StackClass otherStack)
{
list = null;
System.gc();
maxStackSize = otherStack.maxStackSize;
stackTop = otherStack.stackTop;
list = new DataElement[maxStackSize];
//copy otherStack into this stack
for(int i = 0; i < stackTop; i++)
list[i] = otherStack.list[i].getCopy();
}//end copy
//copy constructor
public StackClass(StackClass otherStack)
{
copy(otherStack);
}//end constructor
//Method to make a copy of otherStack.
//Postcondition: A copy of otherStack is created and
// assigned to this stack.
public void copyStack(StackClass otherStack)
{
if(this != otherStack) //avoid self-copy
copy(otherStack);
}//end copyStack
//Method to determine if a given stack has the
//same content as the current one
//Postcondition: Returns true if the two stacks have
// same content, false otherwise.
public boolean equalStack(StackClass otherStack)
{
if (this.isEmptyStack() == otherStack.isEmptyStack())
{
try
{
while(top().compareTo( otherStack.top())==0)
{
pop();
otherStack.pop();
}
return false ;
}
catch (StackUnderflowException e)
{
return true;
}
}
else
return false;
}
}
Code:
import java.util.*;
public class TestProgStack
{
public static void main(String[] args)
{
StackClass stack1 = new StackClass();
StackClass stack2 = new StackClass();
try
{
stack1.push(new IntElement(5));
stack1.push(new IntElement(7));
stack1.push(new IntElement(1));
stack1.push(new IntElement(3));
stack1.push(new IntElement(2));
}
catch(StackOverflowException sofe)
{
System.out.println(sofe.toString());
System.exit(0);
}
stack1.copyStack(stack1);
System.out.print("stack1 elements are: ");
while (!stack1.isEmptyStack())
{
System.out.print(stack1.top() + " ");
stack1.pop();
}
System.out.println();
try
{
stack2.push(new IntElement(1));
stack2.push(new IntElement(3));
stack2.push(new IntElement(2));
stack2.push(new IntElement(5));
stack2.push(new IntElement(7));
stack2.push(new IntElement(0));
}
catch(StackOverflowException sofe)
{
System.out.println(sofe.toString());
System.exit(0);
}
stack2.copyStack(stack2);
System.out.print("stack2 elements are: ");
while (!stack2.isEmptyStack())
{
System.out.print(stack2.top() + " ");
stack2.pop();
}
System.out.println();
if(stack1.equalStack(stack2))
System.out.println("The two Stacks have the same content");
else
System.out.println("The two Stacks have NOT the same content");
}
}
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