Barinex() and bar # under the crossbar

[_AF]

When I loop through bars (eg for (bar =1; bar < barCount ;bar++)

BarIndex[bar] does not match the bar displayed under the crossbar (it is always shifted by 1), so when the BarIndex[bar] = x, bar under the crossbar = x+1).
Any idea why ? and what to do in afl , so they much.
Thank you

[RichardScanlan]

Bar index is zero based whereas barcount is number of bars in the array
Just google amibroker barcount versus barindex gives this link
Read down—- Common Coding mistakes

[_AF]

Well, for programmers the only way to access bars is by using BarIndex() function which is zero based. Now imagine that you are not a programmer, but a software tester or a user who try to verify signals produced by a program . They go and view charts to verify signals. Obviously, under the cross bar, bar numbers, which are not zero based, do not much bar numbers generated by programs.
They have all the rights to claim that programs don't work !!

[fxshrat]

@_AF

Obviously, under the cross bar, bar numbers, which are not zero based, do not much bar numbers generated by programs.

Index is not bar number. In C/C++ indexing starts at zero too.

Also see this thread for index vs. bar number.

Does AFL array start with index 0 or 1?

I know this is a basic question but I want to be sure. Does AFL array start with index 0 or 1? From this page, I get the impression that the first bar index in the array is 1. https://www.amibroker.com/guide/h_understandafl.html However, BarIndex() returns an array of zero-based bar number. https://www.amibroker.com/guide/afl/barindex.html So, I am not sure whether an AFL array start with index 0 or 1.

---

Some other external information..

Zero-based numbering - Wikipedia.

Why are zero-based arrays the norm?

@_AF

Well, for programmers the only way to access bars is by using BarIndex() function

Not correct.
E.g. printf( "%g", C[ i ] ); accesses and outputs an element of array (a value at some bar) and is not using BarIndex() function.

Another example:
bar_value = LookUp(C,_DT("2021-12-01")); does not use BarIndex() too to access a bar.

etc.

So as usual there are many ways to access a bar.