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Project

Array-based Stack Implementation in Java

Stack

Presented byAhmad Abbur RehmanKhayam Ahmed

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/*** Test if the stack is logically empty.* @return true if empty, false otherwise.

*/ public boolean isEmpty( ) { return topOfStack == -1;

}

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/*** Make the stack logically empty.*/

public void makeEmpty( ) {topOfStack = -1;}

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/*** Get the most recently inserted item in the stack.* Does not alter the stack.

* @return the most recently inserted item in the stack.* @throws UnderflowException if the stack is empty.*/

public Object top( ) { if ( isEmpty( ) ) throw new UnderflowException( "ArrayStack top" ); return theArray[ topOfStack ];

}

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/*** Remove the most recently inserted item from the stack.* @throws UnderflowException if the stack is empty.

*/ public void pop( ) { if ( isEmpty( ) ) throw new UnderflowException( "ArrayStack pop" );

topOfStack--;}

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/*** Return and remove the most recently inserted item* from the stack.

* @return the most recently inserted item in the stack.* @throws Underflow if the stack is empty.*/

public Object topAndPop( ) { if ( isEmpty( ) ) throw new UnderflowException( "ArrayStack topAndPop" ); return theArray[ topOfStack-- ];

}

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//// ******************PUBLIC OPERATIONS********************// void push( x ) --> Insert x// void pop( ) --> Remove most recently inserted item

// Object top( ) --> Return most recently inserted item// Object topAndPop( ) --> Return and remove most recent item// boolean isEmpty( ) --> Return true if empty; else false// void makeEmpty( ) --> Remove all items// ******************ERRORS********************************// top, pop, or topAndPop on empty stack

Creating Stack Interface

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/*** Protocol for stacks.*/

public interface Stack {/*** Insert a new item into the stack.* @param x the item to insert.*/

void push( Object x );

/*** Remove the most recently inserted item from the stack

.* @exception UnderflowException if the stack is empty.*/

void pop( );

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Thank You