Hello! Today I am going to give complete pseudocode of the stack array implementation.And at the end of the the page,you can find the java implementation of the stack array.
Complete pseudocode of the stack array implementation
class Stack{
fields{
top < - 1;
array S;
CAPACITY <- n ;
}
isEmpty(){
if(top==-1)
return
TRUE;
else
return
FALSE;
}
push(x){
if(CAPACITY
> size()){
top
<-top+1;
S[top]
<- x;
}else{
print("stack
is overflow");
}
}
size(){
return
top;
}
pop(){
if (isEmpty()){
print
("Stack is underflow");
}
else{
temp
<- S[top];
S[top]
<- NULL;
top
<- top-1;
return
temp;
}
}
top(){
if
isEmpty()
print
("NULL");
else
return
S[top];
}
}
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Java Implementation of Stack Array
Note:My advise is try to write your own code snippets.After your creations ,then you can compare that with my implementation.This will be more interesting than reading my code snippet. Sometimes your code may better than me.
public class Stack {
int CAPACITY = 4;
int s[] = new
int[CAPACITY];
int top = -1;
boolean isEmpty() {
if (top == -1) {
return true;
} else {
return false;
}
}
void push(int x) {
if (CAPACITY > top)
{
top = top + 1;
s[top] = x;
} else {
System.out.println("Stack is overflow");
}
}
int size() {
if (isEmpty() == true)
{
return 0;
} else {
return top + 1;
}
}
String pop() {
if (isEmpty() == true)
{
return "Stack
is Underflow";
} else {
int temp = s[top];
//s[top]=null;
top = top - 1;
return
Integer.toString(temp);
}
}
String top() {
if (isEmpty() == true)
{
return
"NULL";
} else {
int temp = s[top];
return
Integer.toString(top);
}
}
}
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BUT HOW WE KNOW THIS IS WORKING OR NOT???
Here is the solution.
Below is the demo class which include comments,"how we are going to test the above stack array implementation".
package datastructures;
/**
*
* @author hasitha
*/
public class StackDemo {
public static void main(String[] args) {
//Create a empty stack
Stack s=new Stack();
//Since there are no
elements at the biginning stage,then the stack is currently underflow
System.out.println(s.pop());
//Check the initial
size of the array stack
System.out.println("Initial size :"+s.size());
//Add 4 elements to the
array stack
s.push(10);
s.push(15);
s.push(4);
s.push(5);
//Now stack size should
be 4
System.out.println("After insrting 4 elements, size
:"+s.size());
//Call pop() method sth
times,will remove and return elements in LIFO manner
System.out.println("1st call for method pop() :"+s.pop());
System.out.println("2st call for method pop() :"+s.pop());
System.out.println("3 st callfor method pop() :"+s.pop());
System.out.println("4 st call for method pop() :"+s.pop());
//Now corrently stack
is empty.Again call for pop() method.This should print"stack is
underflow"
System.out.println("5 st call for method pop() :"+s.pop());
//Check current status
of the stack(empty or not?)
System.out.println("call for isEmpty() :"+s.isEmpty());
}
}
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If there is any amendments, please drop me an email or comment below.
