Could use std::vector<double> to build a graphs

[songshusen]

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ROOT Version: 6.28
Platform: Windows 10
Compiler: visual studio

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Could use std::vector to build a graphs, and give me a example?

[couet]

TGraph constructors are listed here.

[ackuhlma]

Yes you can definitely do this!
A TGraph has constructors which take arrays as arguments.
For example:

TGraph::TGraph	(	Int_t	n,
		const Double_t *	x,
		const Double_t *	y
	)

So if you had:
vector<double> v = {7,8,9};
Then you could use those points as y-values in a TGraph like this:
TGraph g(v.size(), v.data()); // create a TGraph with default x-values
which would make a TGraph with the points (0,7), (1,8), and (2,9).

If you want to specify the x and y values, you would need 2 vectors x and y
TGraph g(x.size(),x.data(), y.data()); //assuming x.size() == y.size()

Hope this helps!
Best,
Andrew