Create Evaluate reverse polish notation.cpp

Author: Meghak1

Evaluate reverse polish notation.cpp

@@ -0,0 +1,42 @@
+class Solution {
+private:
+    long performedOperation(long operand1,long operand2,char op) {
+        switch (op) {
+            case '+':
+                return operand1 + operand2;
+            case '-':
+                return operand1 - operand2;
+            case '*':
+                return operand1 * operand2;
+            case '/':
+                return operand1 / operand2; 
+            default:
+                return 0;
+        }
+    }
+
+    bool isOperator(char ch) {
+        return ch == '+' || ch == '-' || ch == '*' || ch == '/';
+    }
+
+public:
+    int evalRPN(vector<string>& tokens) {
+    stack<long> Stack;
+    for (const string& token : tokens) {
+         if (token.size() == 1 && isOperator(token[0])) {
+                long operand2 = Stack.top();
+                Stack.pop();
+                long operand1 = Stack.top();
+                Stack.pop();
+                Stack.push(performedOperation(operand1, operand2,token[0]));
+            } 
+         else 
+         {
+                Stack.push(stoi(token));
+         }
+      }
+
+   return Stack.top();
+        
+    }
+};