title: C++ overloading + operator not working
body: <p>Hello guys look to my code I'm trying to make a program which asks you to enter the first value by grams And the second value is kilograms and then convert kilograms to grams by an overloaded + operator but it doesn't work why</p>
  
  <pre><code>#include &lt;iostream&gt;
  using namespace std;
  class ADD{
  private:
      int Fval;
      int Sval;
  public:
      ADD(){
              cout &lt;&lt; "WELCOME TO OUR PROGRAM"&lt;&lt;endl&lt;&lt;"PLEASE ENTER THE FIRST VALUE BY GRAMS :";
              cin &gt;&gt; Fval;
              cout &lt;&lt; "PLEASE ENTER THE SECOND VALUE BY KILOGRAMS :"; cin &gt;&gt; Sval;
          }
      ADD operator+(ADD&amp; add){
          add.Sval *= 1000;
          return add;
      }
      int plus(){
          return Fval+Sval;
      }
  };
  int main(){
      ADD a1;
      cout &lt;&lt; "THE TOTAL VALUE = " &lt;&lt; a1.plus() &lt;&lt; " GRAMS";
  }
  </code></pre>
  
  <p>No Effect look to the output</p>
  
  <pre><code>WELCOME TO OUR PROGRAM
  PLEASE ENTER THE FIRST VALUE BY GRAMS :2
  PLEASE ENTER THE SECOND VALUE BY KILOGRAMS :3
  THE TOTAL VALUE = 5 GRAMS
  </code></pre>
  
  <p>That means the + operator doesn't multiply 3 by 1000
  Why?? </p>