33import java .io .Serializable ;
44import java .util .EmptyStackException ;
55
6- public class Stack <E >implements Serializable {
6+ public class Stack <E >implements Serializable {
77
88/**
9- *Inital capacityalloted to stack on object creation
9+ *Initial capacityallocated to stack on object creation
1010 */
1111private final int INITIAL_CAPACITY =10 ;
1212
1313/**
1414 * Increment in memory space once stack is out of space
1515 */
16- private final int EXNTEDED_CAPACITY =10 ;
16+ private final int EXTENDED_CAPACITY =10 ;
1717
1818
1919/**
@@ -30,15 +30,14 @@ public class Stack<E> implements Serializable {
3030
3131/**
3232 * Uninitialized array to hold stack elements.
33- * WIll beintialized withinital capacity once the object is created
33+ * WIll beinitialized withinitial capacity once the object is created
3434 */
3535private Object []elements ;
3636
3737/**
38- * No argument to create stack object withinital capacity
38+ * No argument to create stack object withinitial capacity
3939 */
4040public Stack () {
41-
4241elements =new Object [INITIAL_CAPACITY ];
4342 }
4443
@@ -47,16 +46,7 @@ public Stack() {
4746 */
4847
4948public boolean empty () {
50-
51- if (null ==elements ) {
52- return true ;
53- }
54-
55- if (size ==0 ){
56- return true ;
57- }
58-
59- return false ;
49+ return elements ==null ||size ==0 ;
6050 }
6151
6252
@@ -65,21 +55,19 @@ public boolean empty() {
6555 */
6656
6757public Object peek () {
58+ if (empty ()) {
59+ throw new EmptyStackException ();
60+ }
6861
69- if (empty ()) {
70- throw new EmptyStackException ();
71- }
72-
73- return elements [tail ];
62+ return elements [tail ];
7463 }
7564
7665/**
7766 * Method to remove the top element from stack
7867 */
7968
8069public Object pop () {
81-
82- if (empty ()) {
70+ if (empty ()) {
8371throw new EmptyStackException ();
8472 }
8573
@@ -95,12 +83,12 @@ public Object pop() {
9583public Object push (Object e ) {
9684
9785boolean isSuccess =false ;
98- if (tail < (INITIAL_CAPACITY -1 )){
86+ if tail < (INITIAL_CAPACITY -1 ))
9987tail ++;
10088elements [tail ] =e ;
101- }else {
102- Object []extendedElements =new Object [INITIAL_CAPACITY +EXNTEDED_CAPACITY ];
103- System .arraycopy (elements ,0 ,extendedElements ,0 , (tail + 1 ));
89+ }else
90+ Object []extendedElements =new Object [INITIAL_CAPACITY +EXTENDED_CAPACITY ];
91+ System .arraycopy (elements ,0 ,extendedElements ,0 , (tail + 1 ));
10492elements =extendedElements ;
10593tail ++;
10694elements [tail ] =e ;
@@ -118,19 +106,19 @@ public int search(Object o) {
118106
119107int index = -1 ;
120108boolean found =false ;
121- if (empty ()) {
109+ if empty ()) {
122110return -1 ;
123111 }
124112
125- for (int i = 0 ;i < size ();i ++) {
126- if (elements [i ] ==o ) {
113+ for int i = 0 ;i < size ();i ++) {
114+ if elements [i ] ==o ) {
127115index =i ;
128116found =true ;
129117break ;
130118 }
131119 }
132120
133- if (found ) {
121+ if found ) {
134122index =tail -index +1 ;
135123 }
136124
@@ -143,5 +131,4 @@ public int search(Object o) {
143131public int size () {
144132return size ;
145133 }
146-
147134}