How to draw new graph with new point?

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ROOT Version: 6.24/06
Platform: Mac Apple M1
Compiler: XCODE 12

I wanted to ask for a information.
I am studying ROOT.
I have 100 files and each file has 9 columns.
I need to take the x data of the first column and for every other y the relative values.
using the push_back method i create the vectors X and Y[8].

Now to normalize it, I need to take the smallest value among the elements of X and translate all the points and make a graph with all the points translated.

I wanted to ask where I am going wrong.

M= 8 columns
I = 100 file with 9 columns-- 1 for X and 8 for Y — for (int i=0; i<N; i++){ etc…

int npoints = (int)X.size();
            for (int k=0; k<M; k++) {
                g[i][k]= new TGraph();
                g[i][k]->SetNameTitle( Form("graphic_name_%d_%d",i,k), Form("graphic_name_ %d_%d",i,k) );
              for (int p=0; p<M; p++) {
                    for( int b=0; b<npoints; b++){
                       float a=X[0];
                        double t;

please,can you help me?

The code sample you posted cannot work (for instance i is not defined) can you post something running with, may be, 2 files instead of 100 so we can study what you are doing and understand what’s wrong.