Question

You may not use the java.util.Stack class.
You may not use the java.util.Queue class.
Write method showStack(): It displays the contents of the stack starting with the first inserted element to the last. The stack would contain the same elements after showStack(). . If for example if to an empty stackx we push(20) then push(30) showStack() would print 20 30

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// stack.java
// demonstrates stacks
// to run this program: C>java StackApp
////////////////////////////////////////////////////////////////
class StackX
{
private int maxSize; // size of stack array
private long[] stackArray;
private int top; // top of stack
//--------------------------------------------------------------
public StackX(int s) // constructor
{
maxSize = s; // set array size
stackArray = new long[maxSize]; // create array
top = -1; // no items yet
}
//--------------------------------------------------------------
public void push(long j) // put item on top of stack
{
stackArray[++top] = j; // increment top, insert item
}
//--------------------------------------------------------------
public long pop() // take item from top of stack
{
return stackArray[top--]; // access item, decrement top
}
//--------------------------------------------------------------
public long peek() // peek at top of stack
{
return stackArray[top];
}
//--------------------------------------------------------------
public boolean isEmpty() // true if stack is empty
{
return (top == -1);
}
//--------------------------------------------------------------
public boolean isFull() // true if stack is full
{
return (top == maxSize-1);
}
//--------------------------------------------------------------
} // end class StackX
////////////////////////////////////////////////////////////////
class StackApp
{
public static void main(String[] args)
{
StackX theStack = new StackX(10); // make new stack
theStack.push(20); // push items onto stack
theStack.push(40);
theStack.push(60);
theStack.push(80);

while( !theStack.isEmpty() ) // until it's empty,
{ // delete item from stack
long value = theStack.pop();
System.out.print(value); // display it
System.out.print(" ");
} // end while
System.out.println("");
} // end main()
} // end class StackApp
////////////////////////////////////////////////////////////////

TEST WITH, DONT CHANGE ANYTHING IN STACKTEST.JAVA

public class StackTest
{
    public static void main(String[] args)
    {
        StackX theStack = new StackX(10);  // make new stack
        theStack.push(20);               // push items onto stack
        theStack.push(30);
        theStack.push(40);
        theStack.push(40);
        theStack.push(60);
        theStack.push(80);

        theStack.showStack();

        System.out.println("removeDownTo(40)");
        theStack.removeDownTo(40);

        theStack.showStack();

    }  // end main()
}

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IF U TRY TO RUN THE CODES U WILL SEE AN ERROR IN STACKTEST.JAVA, AS IT ASKS FOR METHOD SHOWSTACK TO BE IMPLEMENTED IN STACKX.JAVA

Answer 1

Program Code [JAVA]

StackX.java

class StackX
{
    private int maxSize; // size of stack array
    private long[] stackArray;
    private int top; // top of stack
    //--------------------------------------------------------------
    public StackX(int s) // constructor
    {
        maxSize = s; // set array size
        stackArray = new long[maxSize]; // create array
        top = -1; // no items yet
    }
    //--------------------------------------------------------------
    public void push(long j) // put item on top of stack
    {
        stackArray[++top] = j; // increment top, insert item
    }
    //--------------------------------------------------------------
    public long pop() // take item from top of stack
    {
        return stackArray[top--]; // access item, decrement top
    }
    //--------------------------------------------------------------
    public long peek() // peek at top of stack
    {
        return stackArray[top];
    }
    //--------------------------------------------------------------
    public boolean isEmpty() // true if stack is empty
    {
        return (top == -1);
    }
    //--------------------------------------------------------------
    public boolean isFull() // true if stack is full
    {
        return (top == maxSize-1);
    }
    //--------------------------------------------------------------
    public void showStack() // shows contents of stack without deleting them
    {
        // Just Iterating over array and showing elements in it

        for (int i=0; i<=top; i++)
            System.out.print(stackArray[i] + " ");
    }
//--------------------------------------------------------------
} // end class StackX

StackTest.java

public class StackTest
{
    public static void main(String[] args)
    {
        StackX theStack = new StackX(10);  // make new stack
        theStack.push(20);               // push items onto stack
        theStack.push(30);
        theStack.push(40);
        theStack.push(40);
        theStack.push(60);
        theStack.push(80);

        theStack.showStack();


    }  // end main()
}

Sample Output:-

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