file1.h
....
public:
TH1I *fHpx_waveMCA;
TAxis* x_waveMCA;
TAxis* y_waveMCA;
Int_t xmaxint_waveMCA;
Int_t xminint_waveMCA;
Double_t xmaxdt;
Double_t xmindt;
Double_t ymaxdt;
Double_t ymindt;
TCanvas *c124;
.....

file1.cpp
...
int Wind1::load_data(unsigned short mod3333, unsigned short chan3333)
{
	int retval;
	unsigned int NumWords ;
	NumWords = 32768;
	char hname1[10] =  "MCA" ;
	if (tracehist == NULL)
		tracehist = new unsigned int[NumWords];
	memset(tracehist, 0, NumWords * sizeof(unsigned int));
	printf("Reading Histogram from module: module no:%i , chan no.:%i \n",mod3333, chan3333);
	Getdata (tracehist, NumWords, mod3333, chan3333);
	if(retval < 0)
	{
	// error handling
		if (retval == -1)
		......
		return 0;
	}
char title01[20] = "data from module" ;
sprintf(histtitle,"%s,mod=%d,chan=%d", title01 ,mod3333, chan3333);
	if (fHpx_waveMCA == NULL ) {
		 	fHpx_waveMCA = new TH1I ( hname1 , histtitle , NumWords, 0, NumWords );  
			gStyle->SetOptStat(0);
			x_waveMCA = fHpx_waveMCA->GetXaxis();
		//	y_waveMCA = fHpx_waveMCA->GetYaxis(); // for y-axis
				    }
	fHpx_waveMCA->UseCurrentStyle();
	xmaxint_waveMCA = x_waveMCA->GetLast();
	xminint_waveMCA = x_waveMCA->GetFirst();
//  for y - axis
//	ymaxdt = fHpx_waveMCA->GetMaximum();
//	ymindt = fHpx_waveMCA->GetMinimum();
 	fHpx_waveMCA = new TH1I ( hname1 , histtitle , NumWords, 0, NumWords );  
	fHpx_waveMCA->Reset();
	for ( int i = 0; i < NumWords ; i++)
		{  fHpx_waveMCA->Fill(i, int(tracehist[i]) );
		}
	xmaxdt = (Double_t) 2000 ; //   xmaxint_waveMCA;
	xmindt = (Double_t) 1000 ; //   xminint_waveMCA;
	fHpx_waveMCA->SetAxisRange(xmindt, xmaxdt, "X");
//	fHpx_waveMCA->SetAxisRange(ymindt, ymaxdt, "Y");  // for y-axis
	c124->cd();
	fHpx_waveMCA->DrawCopy();
	c124->Modified();
	c124->Update();
	gSystem->ProcessEvents();
return 1;
}  // int Wind1::load_data(unsigned short mod3333, unsigned short chan3333)
.....