Stack and cyclic queue using arrays (Java language)

This article will address two issues. First, how to use arrays to implement a stack, and the stack size can be scaled. Second, an array is used to implement a queue. In order to fully utilize the array space, a loop is implemented here to form a cyclic queue.

(1) Implement Stack Based on Array

Package COM. datastructure. stack; import Java. util. *; public class mystack <t> {private object [] array = NULL; private int Capality; private final int defaultsize = 10; private int size = 0; private int Top =-1; Public mystack () {This. capality = This. defaultsize; this. array = new object [this. capality]; this. size = 0;} public mystack (INT Capality) {This. capality = Capality; this. array = new object [Capality]; this. size = 0;} public boo Lean isempty () {return size = 0;} public int size () {return this. size;} public void push (t obj) {If (this. size <this. capality) {This. top ++; this. array [Top] = OBJ; this. size ++;} else {enablecapality (); push (OBJ) ;}} private void enablecapality () {This. capality = This. capality * 2; object [] newarray = new object [this. capality]; system. arraycopy (array, 0, newarray, 0, this. size); this. array = newarray;} public t POP () {If (isempty ()) {Try {Throw new exception ("Stack is empty! ");} Catch (exception e) {// todo auto-generated catch blocke. printstacktrace () ;}t temp = (t) array [this. top]; array [this. top] = NULL; this. top --; this. size --; return temp;} public static void main (string [] ARGs) {// todo auto-generated method stubmystack <integer> stack = new mystack <integer> (); stack. push (1); stack. push (5); stack. push (2); stack. push (4); stack. push (3); While (! Stack. isempty () {system. Out. println (stack. Pop ());}}}

The running result is as follows:

34251

(2) Implement cyclic queue based on Arrays

Package COM. datastructure. stack; public class myqueue {private object [] array = NULL; private int size; private int front; private int back; private Boolean beginflag = true; private Boolean endflag = false; public myqueue (INT size) {array = new object [size]; this. size = size; front = 0; back = 0;} public myqueue () {This (10);} public void enqueue (Object OBJ) {If (isfull ()) {try {Throw new exception ("the queue is full! ");} Catch (exception e) {// todo auto-generated catch blocke. printstacktrace () ;}} array [Back] = OBJ; back = (back + 1) % size;} public object dequeue () {If (isempty ()) try {Throw new exception ("the queue is empty! ");} Catch (exception e) {// todo auto-generated catch blocke. printstacktrace ();} object temp = array [Front]; array [Front] = NULL; front = (front + 1) % size; return temp;} public Boolean isempty () {If (front = back) {If (! Endflag) {endflag = true; return false;} return true;} elsereturn false;} private Boolean isfull () {If (back + 1) % size = front) {If (beginflag) {beginflag = false; return false;} return true;} else {return false;} public static void main (string [] ARGs) {// todo auto-generated method stubmyqueue queue = new myqueue (5); queue. enqueue (1); queue. enqueue (2); queue. enqueue (3); queue. enqueue (4); queue. enqueue (5); system. out. println (queue. dequeue (); system. out. println (queue. dequeue (); system. out. println (queue. dequeue (); queue. enqueue (5); system. out. println (queue. dequeue (); system. out. println (queue. dequeue (); system. out. println (queue. dequeue (); queue. enqueue (6); system. out. println (queue. dequeue ());}}

The running result is as follows:

1234556