text: //MVC pattern : model view pattern.... design strategy
  
  
  
  
  
  
  //
  //function calculate(firstno,secondno,operator){
  //    
  //       var expression = firstno + operator + secondno;
  //       console.log("expression is ",expression);
  //       return eval(expression);  //eval evaluate expression
  //}
  
  
  
  
  
  
  
  
  
  
  
  
  var calcObject={
      add:function(x,y){
      return parseInt(x)+parseInt(y);
  },
  
      subtract:function(x,y){
      return x-y;
  },
  
      multiply:function(x,y){
      return x*y;
  },
  
       divide:function(x,y){
      return x/y;
  }
  
  }
  
  
  
  
  //function add(x,y){
  //    return parseInt(x)+parseInt(y);
  //}
  //
      //function subtract(x,y){
  //    return x-y;
  //}
  //
  //function multiply(x,y){
  //    return x*y;
  //}
  //
  //function divide(x,y){
  //    return x/y;
  //}