How to create a histogam from a .dat file

[mrc1104]

I know this question has been asked a lot on this site but I cannot find an example that pertains to my current situation. I have a .dat that has data for a time calibration spectrum. My problem is that it is just a wall of values (eg 0000000…000324000…0000000 continuously for 411 lines).

I’ve tried using TFile to open the file and

“TH1F *h1(TH1F *)TFile->Get();”

to read in the data but it is not a ROOT File. So then I tried a variant with ifstream but ifstream is not a pointer. Any advice?

[Wile_E_Coyote]

Filling Histograms with a text file

Try: /* Usage examples: root [0] .L Am241.cxx root [1] Am241(); // expects "Am241.txt" in the current directory root [1] Am241("/full/path/to/some/Am241.txt"); or simply: root [0] .x Am241.cxx root [0] .x Am241.cxx("/full/path/to/some/Am241.txt") */ #include "TGraph.h" #include <fstream> void Am241(const char *file = "Am241.txt") { if ((!file) || (!file[0])) return; // just a precaution TGraph *g = new TGraph(); g->SetTitle("Count Rate;N_{counts};# occurencies"); double y;…