Multipurpose "variable"

[urbmiranda]

Hi,

I am using the term "variable" in this question as defined in the dictionary and not necesarely as used in programing in NT (which I am new to, and were given my current level of confusion may not be the same thing).

I would like to have a variable in my code that I can use in diferent indicators or other parts of the code for say comparison purposes versus other numbers or conditions. How do I create this "variable" and where in the code do I insert it so that the program can look it up every time I call it?

Many thanks

[NinjaTrader_Matthew]

Hello,

You can create a Boolean variable which can be switched to true under certain conditions. Please have a look at the pseudo code below

bool myBool = false;

if (Close[0] > Close[1])
{
  myBool = true;
}

if (myBool == true)
//use this logic

else if (myBool == false)
// use this logic

[urbmiranda]

Thanks Matt, will this allow me to change it in the backtesting window to any value?

[NinjaTrader_Matthew]

The example I gave you was a private variable, but you can make a public Bool which you could change when backtesting.

Please see our Reference Sample on User Defined Input parameters:

http://www.ninjatrader.com/support/forum/showthread.php?t=5782

Instead of an "int" you would use a "bool".

[urbmiranda]

What is the diference between "public" and "private"?

[NinjaTrader_Matthew]

The public variable will give you the ability to set this variable from the grid parameters.

[urbmiranda]

Matt I've followed the procedure you posted and I am getting the following error:

"The type'ninjaTrader.Strategy.Test'already contains a definition for variableX"

Then NT highlights the code

get { return variableX; }

as the source of the problem . I have added the "public double" code in the parameters section for the variable and the "private double" code in the variables section just as the wizard had done with others.

[NinjaTrader_Matthew]

You will want to set it like this:

    #region Variables

     private bool variableX;
     #end reigion

....

     #region Properties

        [Description("")]
        [GridCategory("Parameters")]
        public bool VariableX
        {
            get { return variableX; }
            set { variableX = value; }
        }		
        #endregion

[urbmiranda]

couple things:

1) the variable I am defining is a decimal number, shouldnt I be using the "double" instead of the "bool"?

2) I want this variable to have a default setting of say 2. In that case shouldnt the code in the variables region be :

private double variableX = 2;

instead of your suggested

privatedouble variableX;

[NinjaTrader_Matthew]

Hello,

Yes, if you're dealing with a decimal, you'd want to use a double.

Yes, when you declare the private double, use a value of 2;

[urbmiranda]

Thanks for your patience Matt, I am able to define the variable but the problem in the "parameters" region remains and so does the error message described earlier. So so far I am able to define the variable but not able to have it modifiable in the backtesting window.

[urbmiranda]

"your strategy likely holds one or more recursive properties which could cause ninja trader to crash: varableX"

then highlights the following in the parameters section:

get { return variableX; }

[NinjaTrader_Matthew]

Do you have public int VariableX captialized or lowercase? Please make sure it is capitalize where you are declaring the public int.

[urbmiranda]

Getting nowhere and my NT just crashed.

[NinjaTrader_Matthew]

Can you provide the entire code you are using.