I get the undeclared identifier error and dont know how to fix it

[Krimelio]

 I'm new at learning to code, so im trying to add the standard deviation bands, to a VWAP indicator code I found on the Internet but I get the "FirstDevDaily" undeclared identifier error and dont know how to fix it.

//--- Standard Deviations Calculations ---

     if (Enable_1stStdDev && Enable_Daily)

     {

          for (nIdx=0; nIdx<rates_total; nIdx++)

          {

          nSDDailyTPV += nTotalTPV[nIdx];

          nSDDailyVol += nTotalVol[nIdx];

          nDailyVWAP[nIdx]               =0;

          double FirstMeanDaily[nIdx]    =0;      // To Calculate the mean of the VWAP

          double FirstDevDaily[nIdx]     =0;      // The standard deviation is the square root of the previous numbers

          VWAP_Buffer_1stUpperBand[nIdx] =EMPTY_VALUE;

          VWAP_Buffer_1stLowerBand[nIdx] =EMPTY_VALUE;

          

               nDailyVWAP[nIdx]=(nSDDailyTPV[nIdx]/nSDDailyVol[nIdx]);

               FirstMeanDaily[nIdx]=nDailyVWAP[nIdx].Mean;

               FirstDevDaily+=pow(nDailyVWAP[nIdx]-FirstMeanDaily[nIdx],2);

               FirstDevDaily=sqrt(FirstDevDaily/nIdx);

           }

           

           if (nSumDailyVol)

           {

               VWAP_Buffer_1stUpperBand[nIdx]=(FirstMeanDaily+FirstDevDaily);

               VWAP_Buffer_1stLowerBand[nIdx]=(FirstMeanDaily-FirstDevDaily);

           }

     }

//----------------------------------------

any help to improve the code will be appreciated, thanks

[Miguel Angel Vico Alba]

Krimelio:

Hi Krimelio,

to share code use the 'Code' button. I have corrected this for this time.

[Carl Schreiber]

Every variable has to be declared before you can use it. See:

https://www.mql5.com/en/articles/100
https://www.mql5.com/en/articles/496

[Krimelio]

thanks