diff --git a/calculator.cc b/calculator.cc
index 77a5804..232e776 100644
--- a/calculator.cc
+++ b/calculator.cc
@@ -21,10 +21,12 @@ double Calculator::evaluate(std::string expression)
     v1=v2=0;
     for(int i=0;i < expression.length();i++)
     {
+        // ignore the spaces
         if (isspace(expression[i])){
             continue;
         }
 
+        // Push to stack, if digit
         if(isdigit(expression[i]))
         {
             std::string str;
@@ -36,8 +38,10 @@ double Calculator::evaluate(std::string expression)
             }
 
             mStack.push(stof(str));
+            // Decrease index as currently points to advanced element
             i--;
         }
+        // Check if operator and perform the operation of numbers from stack
         else if (IsOperator(expression[i])){
             if (expression[i] == '+'){
                 v1 = mStack.top();
@@ -68,10 +72,11 @@ double Calculator::evaluate(std::string expression)
                 ret = v2/v1;
             }
 
+            // push the final result
             mStack.push(ret);
         }
         }
-    //Return answer
+    // return answer
     return mStack.top();
 }
 
diff --git a/calculator.h b/calculator.h
index d191725..63a4ed6 100644
--- a/calculator.h
+++ b/calculator.h
@@ -7,9 +7,14 @@ class Calculator {
     Calculator() = default;
     ~Calculator() = default;
 
+    /**
+     * method to evaluate the expression
+     */
     double evaluate(std::string expression);
 
 private:
+
+    //Stack to hold the numbers
     std::stack<float> mStack;
     bool IsOperator(char c);   
 };
diff --git a/main.cc b/main.cc
index 3594508..ba5bd96 100644
--- a/main.cc
+++ b/main.cc
@@ -7,9 +7,8 @@ int main() {
 
   dev::Calculator calc;
   std::string s;
-  std::cout<<"enter the string: ";
+  std::cout<<"Enter the string: ";
   std::getline(std::cin,s);
-
   std::cout<<"Result:"<<calc.evaluate(s)<<std::endl;
 
   dev::Project p;