C++ program read from 2 txt files

i had written a script to read 2 txt files (contains 3 coulmns for each ) and need to know how to link the arraies in the script with the files
the code in the attachment
try1.c (952 Bytes)

Try: { // open ROOT file to save the TTree and histograms TFile *ftree = new TFile("tree_nucnet.root", "recreate"); // creation of TTree TTree *tree = new TTree("YU_NUCNET_TOOLS", "YU_NUCNET_TOOLS"); // creation and filling of branches to hold the variables tree->ReadFile("The_First_Data_File.txt", "Time/F:H_mass:He_mass"); tree->ReadFile("The_Second_Data_File.txt"); // tree->ReadFile("The_Third_Data_File.txt"); tree->Write(); // creation of histograms TH1F *h1 = new TH1F("h1", "1H vs. Time", 100, 0, 3.15e16); TH1F *h2 = new TH1F("h2", "4He vs. Time", 100, 0, 3.15e16); // filling the histograms tree->Project("h1", "H_mass"); h1->Write(); tree->Project("h2", "He_mass"); h2->Write(); // drawing histograms TCanvas *c = new TCanvas("c", "c"); c->Divide(1, 2); c->cd(1); h1->Draw(); c->cd(2); h2->Draw(); c->cd(0); // delete ftree; // automatically deletes "tree", "h1" and "h2", too }

thank you Mr Pepe Le Pew for your reply but still i need to specify the columns i need to plot such as
plot the second column from the first file at x-axis with the third column from the second file at y-axis
how i can do that
and thanks again