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[User Discussion] - sc. structure passed by reference as default value to all functions

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[2021-03-08 17:17:22]
[Go To First Post]
User30743 - Posts: 365
is there any way to pass sc structure to custom functions by &reference, and having it as a default value?

here is what i mean..

For example I have a class like this

namespace util{
class Logger {
public:
static void log(SCStudyInterfaceRef& sc, SCDateTime value, SCString comment = "") {
SCString s = sc.FormatDateTime(value).GetChars();
comment += s;
sc.AddMessageToLog(comment, 1);
}

static void log(SCStudyInterfaceRef& sc, const char* value, SCString comment = "") {
comment += value;
sc.AddMessageToLog(comment, 1);
}

static void log(SCStudyInterfaceRef& sc, int value, SCString comment = "") {
SCString strVal = std::to_string(value).c_str();
comment += strVal;
sc.AddMessageToLog(comment, 1);
}
};

The first argument is of course SCStudyInterfaceRef which I am passing via ref &.

then the called needs to pass this argument sc


SCSFExport scsf_LogUtilsTest(SCStudyInterfaceRef sc) {

SCDateTime TradingDayStartDateTime = sc.GetTradingDayStartDateTimeOfBar(sc.BaseDateTimeIn[sc.IndexOfLastVisibleBar]);

util::Logger::log(sc, TradingDayStartDateTime);
util::Logger::log(sc, 3.23);
}

But, it is tedious to pass sc all the time everywhere. I would like to make it default in all my custom functions because it is obvious it will be passed there, there is no other option anyway

But I did not figure out how to make it work.

Any suggestions?
Date Time Of Last Edit: 2021-03-08 17:20:28
[2021-03-08 18:39:40]
[Go To First Post]
User907968 - Posts: 833
is there any way to pass sc structure to custom functions by &reference, and having it as a default value?
No not in the way that you want, because you are passing a reference to a specific instance of sc structure/object that relates to the chart/study.

Also 'SCStudyInterfaceRef' is already alias for 's_sc&' therefore additional '&' is not needed.

typedef s_sc& SCStudyInterfaceRef;
Date Time Of Last Edit: 2021-03-08 18:41:09
[2021-03-09 18:04:53]
[Go To First Post]
User30743 - Posts: 365
so how do i make it that i will not have to pass sc everytime?
[2021-03-09 20:38:31]
[Go To First Post]
norvik_ - Posts: 106
namespace util{

class Logger {

public:

Logger(SCStudyInterfaceRef sc):p_Interface(&sc)

static void log(const SCDateTime& value, SCString comment = "")
{

SCString s = p_Interface->FormatDateTime(value).GetChars();

comment += s;

p_Interface->AddMessageToLog(comment, 1);

}

private:

s_sc* p_Interface;
};

or make a singleton.


class Logger
{

public:

static Logger& Instance(){static Logger l;return ;l}
void Attach(SCStudyInterfaceRef sc){p_Interface = ≻}

void log(const SCDateTime& value, SCString comment = "")
{

SCString s = p_Interface->FormatDateTime(value).GetChars();

comment += s;

p_Interface->AddMessageToLog(comment, 1);

}

private:
Logger(){}
s_sc* p_Interface;
};

and use:

Logger::Instance().Attach(sc);
Logger::Instance().log(value,comment);
Date Time Of Last Edit: 2021-03-09 20:42:24
[2021-03-10 08:59:55]
[Go To First Post]
User30743 - Posts: 365
wow

what is this
Logger(SCStudyInterfaceRef sc):p_Interface(&sc)
? Logger is inheriting from p_Interface(&sc)?

and at the same time it is having
s_sc* p_Interface;
as private member?

well, this is quite a new construct for me.

I am still a c++ beginner so sorry is this is a dumb question.. can u explain me ?
Date Time Of Last Edit: 2021-03-10 09:00:46
[2021-03-10 19:15:13]
[Go To First Post]
norvik_ - Posts: 106
Hi. No inheritance in my first sample. It is class constructor with the reference to the s_sc structure as constructor parameter, that is all. I think it is a not very good idea to use s_sc to inherit your own class from it, but you can try, I never had checked.
As for private state of p_Interface, the only one reason, you will never use it outside a class, so simply no sense make it public.
Date Time Of Last Edit: 2021-03-10 20:17:08
[2021-03-16 19:35:21]
[Go To First Post]
User30743 - Posts: 365
Logger(SCStudyInterfaceRef sc):p_Interface(&sc)

is a constructor with s_sc as parameter? Really strange.

I have never seen anything like this in C++ before. And it cannot be compiled by the way.

Isnt this just a totally invalid construct?
Date Time Of Last Edit: 2021-03-16 19:53:48
[2021-03-16 21:54:19]
[Go To First Post]
User907968 - Posts: 833
Isnt this just a totally invalid construct?
No, just one form of initialization.

https://en.cppreference.com/w/cpp/language/direct_initialization
https://en.cppreference.com/w/cpp/language/list_initialization

I found this book useful when starting out with c++ - https://www.stroustrup.com/programming.html
Date Time Of Last Edit: 2021-03-16 21:59:31
[2021-03-17 12:31:31]
[Go To First Post]
User30743 - Posts: 365
ok, then why it cannot be compiled?
[2021-03-17 13:27:17]
[Go To First Post]
User907968 - Posts: 833

namespace util{
class Logger {
public:

Logger(SCStudyInterfaceRef sc):p_Interface(&sc) {}

void log(const SCDateTime& value, SCString comment = "")
{
SCString s = p_Interface->FormatDateTime(value).GetChars();
comment += s;
p_Interface->AddMessageToLog(comment, 1);
}

private:
s_sc* p_Interface;

};
}

Cannot have static function that references non-static member, also add braces to constructor.
[2021-03-17 19:19:31]
[Go To First Post]
User30743 - Posts: 365
oh, now I understand. thank u!

is there a way to make it work also for static members?

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