Merge pull request #72 from Gargee07/Branch-for-Stack-using-two-queue…

…s-Code

Solution to Issue #56 Stack using two queues

Main.java

@@ -0,0 +1,49 @@
+/* 
+ * Implementation of Stack using two Queue
+ */
+package stackUsingQueues;
+import java.util.*;
+
+class Stack{  					// Stack class where all methods of stack are created 
+	Queue<Integer> q1 = new LinkedList<Integer>(); 
+	Queue<Integer> q2 = new LinkedList<Integer>();
+
+//using Push Operation costly approach
+void push(int element) {  
+
+	q2.add(element);    //adding recently entered element to q2
+
+	while (!q1.isEmpty()) {    
+		q2.add(q1.peek());	 // moving all the elements of q1 to q2 
+		q1.remove(); 
+	} 
+
+	Queue<Integer> temp = q1;   
+	q1 = q2; 				//swapping the queues
+	q2 = temp;
+}
+
+
+int pop() {  				// returns and remove the recently entered element
+	if (q1.isEmpty()) {
+		return -1; } //returns -1 for empty queue
+	else{
+		return q1.remove(); 
+	}
+}
+}
+public class Main {  //Main class
+
+	public static void main(String[] args) {
+		Scanner input=new Scanner (System.in);
+		Stack stack=new Stack();   //Instantiating Stack class
+		stack.push(2);
+		stack.push(3);
+		System.out.print(stack.pop()+" ");
+		stack.push(4);
+		System.out.print(stack.pop()+" ");
+
+
+		input.close();
+	}
+}

Stack_Using_Queues.java

@@ -0,0 +1,53 @@
+/* 
+ * Implementation of Stack using two Queue
+ */
+package stackImplementation;
+import java.util.*;
+
+
+	class Stack{  					// Stack class where all methods of stack are created 
+	Queue<Integer> q1 = new LinkedList<Integer>(); 
+	Queue<Integer> q2 = new LinkedList<Integer>();
+
+	//using Push Operation costly approach
+	void push(int element) {  
+
+		q2.add(element);    //adding recently entered element to q2
+
+		while (!q1.isEmpty()) {    
+			q2.add(q1.peek());	 // moving all the elements of q1 to q2 
+			q1.remove(); 
+		} 
+
+		Queue<Integer> temp = q1;   
+		q1 = q2; 				//swapping the queues
+		q2 = temp;
+	}
+
+
+	int pop() {  				// returns and remove the recently entered element
+		if (q1.isEmpty()) { 
+			return -1; } //returns -1 for empty queue
+		else{
+			return q1.remove(); 
+		}
+	}
+}
+
+public class Stack_Using_Queues {
+
+	public static void main(String[] args) {
+		Scanner input=new Scanner (System.in);
+		Stack stack=new Stack();   //Instantiating Stack class
+		stack.push(2);
+		stack.push(3);
+		System.out.print(stack.pop()+" ");
+		stack.push(4);
+		System.out.print(stack.pop()+" ");
+
+
+
+		input.close();
+	}
+
+}