From e7f35ab8dffb7c2efeda42d45a779634c1a6fdb2 Mon Sep 17 00:00:00 2001
From: Manmeet Singh <manmeet-22@users.noreply.github.com>
Date: Mon, 2 Oct 2017 00:42:20 +0530
Subject: [PATCH 1/2] Postfix Notation using Stack

Note- Give input in the form like "1 21 + 45 13 + *"
#96
---
 Misc/StackPostfixNotation | 38 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 38 insertions(+)
 create mode 100644 Misc/StackPostfixNotation

diff --git a/Misc/StackPostfixNotation b/Misc/StackPostfixNotation
new file mode 100644
index 000000000..c04b0ac6b
--- /dev/null
+++ b/Misc/StackPostfixNotation
@@ -0,0 +1,38 @@
+import java.util.*;
+
+public class Postfix {
+    public static void main(String[] args) {
+         Scanner scanner = new Scanner(System.in);
+        String post = scanner.nextLine();   // Takes input with spaces in between eg. "1 21 +"
+        System.out.println(postfixEvaluate(post));
+    }
+
+    // Evaluates the given postfix expression string and returns the result.
+    public static int postfixEvaluate(String exp) {
+	 	Stack<Integer> s = new Stack<Integer> ();
+		Scanner tokens = new Scanner(exp);
+
+		while (tokens.hasNext()) {
+			if (tokens.hasNextInt()) {
+				s.push(tokens.nextInt()); // If int then push to stack
+			} else {    // else pop top two values and perform the operation
+				int num2 = s.pop();
+				int num1 = s.pop();
+				String op = tokens.next();
+
+				if (op.equals("+")) {
+					s.push(num1 + num2);
+				} else if (op.equals("-")) {
+					s.push(num1 - num2);
+				} else if (op.equals("*")) {
+					s.push(num1 * num2);
+				} else {
+					s.push(num1 / num2);
+				}
+
+			//  "+", "-", "*", "/"
+			}
+		}
+		return s.pop();
+    }
+}

From ae3342fb50eb5f4a2b973356e8685fb3ac57543a Mon Sep 17 00:00:00 2001
From: Manmeet Singh <manmeet-22@users.noreply.github.com>
Date: Tue, 3 Oct 2017 16:51:42 +0530
Subject: [PATCH 2/2] Added Extension

---
 Misc/{StackPostfixNotation => StackPostfixNotation.java} | 0
 1 file changed, 0 insertions(+), 0 deletions(-)
 rename Misc/{StackPostfixNotation => StackPostfixNotation.java} (100%)

diff --git a/Misc/StackPostfixNotation b/Misc/StackPostfixNotation.java
similarity index 100%
rename from Misc/StackPostfixNotation
rename to Misc/StackPostfixNotation.java