getline : what's wrong with these?

[Harddisk]

Hi, I've 2 pieces of codes here
Grade.cpp

#include <iostream>
#include <string>
#include <fstream>
#include <sstream>

using namespace std;

string ReadLN() {
	string str;
	char ch;
	while (cin.get(ch) && ch != '\n')
		str = str + ch;
	return str;
}

void main() {
	string FileName;
	cout << "Enter name of grades file: ";
	FileName = ReadLN();
	ifstream input(FileName.c_str());
	if (input.fail()) {
		cerr << "Could not open file: " << FileName << endl;
		exit(1);
	}
	
	string line, name, score;
    double sum = 0, average = 0;
	int num, count = 0;

	while (!input.eof()) {
		getline(input, name, ':');
		getline(input, score, '\n');

		// Declare an istringstream object/datatype
		// required #include <sstream>
        istringstream sin(score);

        while (sin >> num) {
            sum += num;
            count++;
        }

		cout << "Average for " << name << ": ";
        if (count != 0) {
            average = sum / count;
			cout << average << endl;
        }
        else {
			cout << "<< Error >>" << endl;
        }
	}
}

Spam.cpp

#include <iostream>
#include <string>
#include <fstream>
#include <sstream>

using namespace std;

string ReadLN() {
	char ch;
	string str;
	while (cin.get(ch) && ch != '\n')
		str = str + ch;
	return str;
}

void main() {
	string strTemplate, strData;
	string strTemplateData, strTmp;
	cout << "Please enter template filename (spam.dat): ";
	strTemplate = ReadLN();
	ifstream fTemp(strTemplate.c_str());
	if (fTemp.fail()) {
		cerr << "Could not open file: " << strTemplate << endl;
		exit(1);
	}

	while (!fTemp.eof()) {
		getline(fTemp, strTmp);
		strTemplateData = strTemplateData + strTmp;
	}
	fTemp.close();

	cout << "Please enter data filename (dummies.dat); ";
	strData = ReadLN();
	ifstream fData(strData.c_str());
	if (fData.fail()) {
		cerr << "Could not open file: " << strData << endl;
		exit(1);
	}

	int intRec = 0;
	string strFName, strLName, strAdd, strCity, strState;
	string strOut;
	while (!fData.eof()) {
		getline(fData, strOut);
		getline(fData, strFName, ":");
		getline(fData, strLName, ":");
		getline(fData, strAdd, ":");
		getline(fData, strCity, ":");
		getline(fData, strState, "\n");

		ofstream fout(intRec + ".spm");
		fout << strTemplateData;
		fout.close();
	}

	cout << "Done!" << endl;
}

Grade.cpp can compile without error, but Spam.cpp has error on the getline(fData, xxxx); part of it.

From the looks of it, both function calls are the same. Is there something that I'm missing?

Thanks for any help.

Harddisk

PS: BTW, the spam code is harmless, just some exercise I m doing.