Hello Rooters,

I was trying to draw 1D histograms for each 2D bins. For that I used 2D array and defined them as follows.

I am getting segmentation error in the following code part.

```
//histogram definition
TH1F *h_pimMX2array_3fold_bgnd[i_theta_bins][n_p];
char histName_3fold_bgnd[64];
for (int ith=0; ith<i_theta_bins; ith++) {
for (int ippim=0; ippim<n_p; ippim++) {
sprintf(histName_3fold_bgnd,"h_pimMX23foldbgndarray_p%03d_th%03d",ippim,ith);
h_pimMX2array_3fold_bgnd[ith][ippim] = new TH1F(histName,"3fold and 4fold Missing pimMassSq",300,-0.5,0.5);
}
}
TCanvas *canEfficiency = new TCanvas("canEfficiency","",12000,6000);
canEfficiency->Divide(4,3);
for (int ith=0; ith<3; ith++) {
for (int ippim=0; ippim<4; ippim++){
double n3bgnd[ith][ippim];
n3bgnd[ith][ippim] =h_pimMX2array_3fold_bgnd[ith][ippim]->GetEntries();
// remove overflows and underflows (should be 0)
n3bgnd[ith][ippim] += -h_pimMX2array_3fold_bgnd[ith][ippim]->GetBinContent(0);
n3bgnd[ith][ippim] += -h_pimMX2array_3fold_bgnd[ith][ippim]->GetBinContent( h_pimMX2array_3fold_bgnd[ith][ippim]->GetNcells()-1); //fault is somewhere in this line???
}
}
```

the break happen in the following line.

```
n3bgnd[ith][ippim] += -h_pimMX2array_3fold_bgnd[ith][ippim]->GetBinContent( h_pimMX2array_3fold_bgnd[ith][ippim]->GetNcells()-1);
```

So I tried this with

```
n3bgnd[ith][ippim] += -h_pimMX2array_3fold_bgnd[ith][ippim]->GetBinContent( h_pimMX2array_3fold_bgnd[ith][ippim]->GetNcells()-1,h_pimMX2array_3fold_bgnd[ith][ippim]->GetNcells()-1 );
```

This also gave me the segmentation fault.

Any help would be greatly appreciated.

Thanks

Dilini