create ROOT histogram from a text file containing entries

makeHistogram.C

void makeHistogram(std::string fileName){
	using namespace std;
	ifstream ifs(fileName.c_str());
	int pi;
	TCanvas* c=new TCanvas("c","c",600,600);
	TH1D* hist=new TH1D("hist",fileName.c_str(),2048,0,2048);
	while(ifs.is_open() && !ifs.eof()){
		ifs >> pi;
		hist->Fill(pi);
	}
	hist->Draw();
	std::string pngFileName=fileName+".png";
	std::string pdfFileName=fileName+".pdf";
	c->SaveAs(pngFileName.c_str());
	c->SaveAs(pdfFileName.c_str());
	ifs.close();
}

Hello, I am happy to have come across your code as i belive it will be the solution to my issue. However, I have ran into an error
"Error: Function makeHistogram() is not define in current scope :0:
Interepreter error recovered"

Did you happen to run into this yourself when executing the code using ".x" in root?

Thanks!!