Histogram scale not showing


I’m trying to create a histogram with the following code;

void test2(){

	//Define lambda_mat (or sigma^2) for a material of given radiation length
	//from lambda_mat = 13.6^2/P0^2/L0.
	double MomIn = 3; //the initial momentum of a muon
	TFormula *variance = new TFormula("variance", "(13.6*13.6)/([0]*[0])/x"); 
	double VarianceIn = variance->Eval(0.98);  // set the radiation length.
	//Generate a histogram from previously calculated variance in the form of a gaussian
	//with a peak at 0 for theta.
	gRandom = new TRandom3();
	TH1D *ThetaHist = new TH1D("Theta", ";x;N", 20, -100, 100.0);
	for (int i = 0; i<10000; ++i)
		ThetaHist -> Fill(gRandom->Gaus(0, VarianceIn));
	TCanvas * ThetaHistC= new TCanvas("ThetaHistC", "random",5,5,800,600);

the histogram is plotted but no values on the x or y axis show anyone know how to fix this?

“AC” draws the histogram as a smooth Curve without axis.