How to avoid array out of range error in mql4 indicator

External question — Stack Overflow Stack Exchange Author: Sam Original post: https://stackoverflow.com/questions/69362649 License: CC BY-SA 4.0 — https://creativecommons.org/licenses/by-sa/4.0/ Adaptation: HTML converted to plain text; contact email addresses removed. How to deal with or handle/avoid the array out of range error here : for(int i=0; i<=ObjectsTotal()-1; i++) { string objName = ObjectName(0,i); if(StringFind(objName,"Last#")>=0) { string tempval= objName; string temtext= ObjectGetString(0,objName,OBJPROP_TEXT); StringReplace(tempval,"Last#",""); int tempnum = (int)(tempval); for(int k=tempnum; k>=tempnum-20; k--) { if( RBuffer1[k] != EMPTY_VALUE) { ObjectDelete(0,objName); DrawText("Last#"+tempnum,Time[tempnum],Low[tempnum],temtext+"_0","Arial",9,clrWhite); break; } else if(RBuffer2[k] != EMPTY_VALUE) { ObjectDelete(0,objName); DrawText("Last#"+tempnum,Time[tempnum],Low[tempnum],temtext+"_1","Arial",9,clrWhite); break; } } } } I am sure there is something wrong with my logic but cant figure out what exactly , and the indicator works fine on some timeframes but on 2 ,3 timeframes it throws the error array out of range This is for(int k=tempnum; k>=tempnum-20; k--) where I am receiving the error.

External answer — Stack Overflow Stack Exchange Author: amirfg Original post: https://stackoverflow.com/a/69496359 License: CC BY-SA 4.0 — https://creativecommons.org/licenses/by-sa/4.0/ Adaptation: HTML converted to plain text; contact email addresses removed. First of all, check the size of "RBuffer1" using "ArraySize": int iArrSize = ArraySize(RBuffer1); if (iArrSize >= 20) { ... } more importantly, the array index starts from 0 up to the predefined size (in your case 20 or 21). But you are trying to access the index 20 up to 41. Obviously, you will receive an "Array out of range" error message. Just change your code to something like: if (RBuffer1[k - 21] != EMPTY_VALUE) { ... }