custom implementation of simple stack

Author: premaseem

src/datastructure/simplestack/App.java

@@ -0,0 +1,28 @@
+package datastructure.simplestack;
+
+public class App {
+    public static void main(String... args) {
+        System.out.println("custom stack implementation");
+        CustomStack theStack = new CustomStack(5);
+        theStack.push(13);
+        theStack.push(23);
+        theStack.push(33);
+        theStack.push(43);
+        theStack.push(53);
+        theStack.push(63);
+        theStack.push(73);
+        theStack.push(83);
+        System.out.println("popped out value "+ theStack.pop());
+
+        theStack.printStack();
+        theStack.pop();
+        theStack.printStack();
+
+        theStack.peak();
+
+        // empty out the stack
+        while (!theStack.isEmpty()){
+            System.out.println("popped out value "+ theStack.pop());
+        }
+    }
+}

src/datastructure/simplestack/CustomStack.java

@@ -0,0 +1,53 @@
+package datastructure.simplestack;
+
+public class CustomStack {
+
+    int top = -1;
+    int maxSize = 10;
+    long[] stackArray;
+
+    public CustomStack(int maxSize){
+        this.maxSize = maxSize;
+        stackArray = new long[maxSize];
+    }
+
+    public void push(int value) {
+        if(isFull()){
+            System.out.println("Cannot add more as stack is already full ");
+        }else {
+            top++;
+            stackArray[top] = value;
+        }
+    }
+
+    public int pop(){
+        if(isEmpty()){
+            System.out.println("Cannot pop more since stack is empty");
+            return -1;
+        }else {
+            int old_top = top;
+            top--;
+            return (int) stackArray[old_top];
+        }
+    }
+
+    public int peak(){
+        System.out.println("top element of stack is");
+        return (int) stackArray[top];
+    }
+
+    public boolean isEmpty(){
+        return top == -1;
+    }
+
+    public boolean isFull(){
+        return top == (maxSize-1);
+    }
+
+    public void printStack(){
+        System.out.println("current values in stack are ");
+        for(int i=0; i<=top;i++){
+            System.out.println(stackArray[i]);
+        }
+    }
+}