Implementing stacks and queues with arrays

This article is a simulation of linkedlist implementation of which: Add, value, queue, out team, into the stack, out of the stack

1. Implementation of dynamic arrays

Package Com.sxt.test.java; Public classArray {protectedobject[] Arrays =Newobject[0]; protectedObject[] Arrays2=NULL;
With each additional element, create a new array that is +1 longer than the original.
Put the data of the original array into a new array, and finally add the new data to the last
Original array Empty Public voidAdd (Object o) {
        if(arrays!=NULL&& arrays2==NULL) {Arrays2=Newobject[arrays.length+1];  for(intI=0; i<arrays.length;i++) {Arrays2[i]=Arrays[i]; } Arrays2[arrays.length]=o; Arrays=NULL; return; }                if(arrays==NULL&& arrays2!=NULL) {Arrays=Newobject[arrays2.length+1];  for(intI=0; i<arrays2.length;i++) {Arrays[i]=Arrays2[i]; } Arrays[arrays2.length]=o; Arrays2=NULL; return; }}//Fetch data, two arrays must have one empty, one with data PublicObjectGet(intindex) {Object o=NULL; Try {            if(arrays!=NULL) {o=Arrays[index]; }            if(arrays2!=NULL) {o=Arrays[index]; }        }Catch(Exception e) {Throw NewRuntimeException ("something went wrong .", E); }        returno; }     Public intLength () {intLength =0; if(arrays!=NULL) {length=arrays.length; }Else        if(arrays2!=NULL) {length=arrays2.length; }        returnlength; }}

2. Implementation of the queue

Package Com.sxt.test.java; Public classQueue extends array{/** * Queue **/     Public voidAdd (Object o) {super.add (o); }    /** * out of the team
* Two arrays must have data, one is empty
* Take out the first data and create a new array that is 1 longer than the previous one
* From the back forward, the data into the new array, the original first data is not put in
* Finally return the first data retrieved **/     PublicObject Poll () {Object o=NULL; if(arrays!=NULL) {o= arrays[0]; Arrays2=Newobject[arrays.length-1];  for(inti=arrays.length-1;i>0; i--) {Arrays2[i-1]=Arrays[i]; } Arrays=NULL; }Else if(arrays2!=NULL) {o= arrays2[0]; Arrays=Newobject[arrays2.length-1];  for(inti=arrays2.length-1;i>0; i--) {arrays[i-1]=Arrays2[i]; } arrays2=NULL; }        returno; }}

3. Implementation of the Stack

Package Com.sxt.test.java; Public classStack extends array{/** * Press Stack **/     Public voidpush (Object o) {super.add (o); }        /** * out of the stack
* Take the last data of the array to return
* Then create an array that is 1 longer than the original, and put the data into a new array before the last data is placed
*
* Finally return the last data retrieved **/     PublicObject Pop () {object o=NULL; if(arrays!=NULL) {o= arrays[arrays.length-1]; Arrays2=Newobject[arrays.length-1];  for(intI=0; i<arrays.length-1; i++) {Arrays2[i]=Arrays[i]; } Arrays=NULL; }Else if(arrays2!=NULL) {o= arrays2[arrays2.length-1]; Arrays=Newobject[arrays2.length-1];  for(intI=0; i<arrays2.length-1; i++) {Arrays[i]=Arrays2[i]; } arrays2=NULL; }        returno; }}

4. Test class

/** * Dynamic Arrays Array Test **/Array a=NewArray (); A.add ("a"); A.add ("b"); A.add ("C"); A.add ("D"); System. out. println (A.length ());  for(intI=0; I<a.length (); i++) {System. out. println (A.Get(i)); } System. out. println ("------------"); /** * Queue Test **/Queue Queue=NewQueue (); Queue.add ("a"); Queue.add ("b"); Queue.add ("C"); Queue.add ("D"); Queue.add ("e"); Queue.add ("F"); System. out. println (Queue.length ());  while(Queue.length () >0) {System. out. println (Queue.poll ()); } System. out. println ("----------"); /** * Stack Test **/Stack Stack=NewStack (); Stack.push ("a"); Stack.push ("b"); Stack.push ("C"); Stack.push ("D"); Stack.push ("e"); Stack.push ("F"); System. out. println (Stack.length ());  while(Stack.length () >0) {System. out. println (Stack.pop ()); }

Implementing stacks and queues with arrays