Array out of range

[Axel D]

Hello everyone! I am new to MQL4. Would love to have some help. I am trying to create an indicator and getting "Array out of range" on the code below for "var[1]". Would anyone know why?

double var[];

for(int i=0; i<rates_total; i++)

        {

                var[i]=Close[i];

        }

Any help would be very much appreciated!

Best regards!

[Keith Watford]

Axelrod D:

Hello everyone! I am new to MQL4. Would love to have some help. I am trying to create an indicator and getting "Array out of range" on the code below for "var[1]". Would anyone know why?

You have to size the array

[Axel D]

you mean add a number here:

double var[SIZE_HERE];

for(int i=0; i<rates_total; i++)

        {

                var[i]=Close[i];

        }

I was wishing to use rates_total. If I understood right, that would include all candles on chart. But still get  "'[' - invalid index value" error with that.

[William Roeder]

Axel D: you mean add a number here:

1. No, because you don't know what the maximum of rates_total will be, you can't declare a constant size.

2. Perhaps you should read the manual.

   ArrayResize The function sets a new size for the first dimension
             ArrayResize - Array Functions - MQL4 Reference

3. Why are you trying to use an array in an indicator. Use a buffer and it will be automatically resized for you.

[Axel D]

As I understood, arrays would work like this on the chart:

https://pasteboard.co/IdNeOhR.png

So I wanted to be able to work using the second-last value from a line (array) in order to create the last value from another one.

Thank you guys very much for the help!

[William Roeder]

1. Please use the link button See the difference? https://pasteboard.co/IdNeOhR.png
             Messages Editor

2. Please don't post a link to or attach an image, just insert the image.
             Messages Editor
   

   

   That is supposed to mean something?
   

3. Axel D:  So I wanted to be able to work using the second-last value from a line (array) in order to create the last value from another one.

   That sounds like gibberish to me. Only the "last value" can create the "last value."
   

[Axel D]

Thank you for the tip!

I will try to explain it better:

Lets say this black line with dots above is line_a. We could then have line_b being always equal to Close as default. Then whenever line_a[1] < Close then line_b[0] = line_a[1].