Repetition of output in a text file.

[Daniel Steel]

So, I wanted to do some practice around fstream, and I decided to make a sort of database where data regarding voters read from a txt file is sorted into two files based on age. Then, the program reads the files with ages over 18, and counts the votes for each political party. I haven't reached the voting part yet, because this error keeps coming where, anytime more then 4 ids are read, the last entry is reread and and repeated into the text file.

The text file layout is like this:
Daniel 18 G
Ken 52 F
Mark 12 X
Riley 17 X
Ian 22 G
Harry 15 F

And the data is then sorted into two files, labelled "Under 18" and "Over 18".
But if the data happens to have more than 4 entries, the last entry will get repeated, something like this:

Name: Harry
Age: 15

Name:
Age: 15

Here is the code:

#include <iostream>
#include <fstream>
using namespace std;

void Data(char[], char, int);
void Over_18(char[], char, int);
void Under_18(char[], char, int);

int main()
{
	char Name[100] = {}, Vote = {};
	int Age = {};

	Data(Name, Vote, Age);
}

void Data(char Name[], char Vote, int Age)
{
	ifstream Main;
	Main.open("Data.txt", ios::app);

	while (!Main.eof())
	{
		Main >> Name;

		if (Name == "0")
		{
			break;
		}

		Main >> Age;
		Main >> Vote;

		if (Age < 18)
		{
			Under_18(Name, Vote, Age);
		}
		else if (Age >= 18)
		{
			Over_18(Name, Vote, Age);
		}

		for (int i = 0; i < 100; i++)
		{
			Name[i] = -52;
		}
	}
}

void Under_18(char Name[], char Vote, int Age)
{
	ofstream f18;
	f18.open("Under 18.txt", ios::app);

	f18 << "Name: " << Name << endl;
	f18 << "Age: " << Age << endl << endl;

	f18.close();
}

void Over_18(char Name[], char Vote, int Age)
{
	ofstream f19;
	f19.open("Over 18.txt", ios::app);

	f19 << "Name: " << Name << endl;
	f19 << "Age: " << Age << endl;
	f19 << "Vote: " << Vote << endl << endl;

	f19.close();
}

I would like to add that yes, I am aware vectors could help, as some people in my previous questions pointed out. But I haven't looked into it yet and I want to find a solution to this problem with just fstream.

[Peter87]

Using .eof() as a loop condition is almost always wrong. The end-of-file flag is not set until you've tried to read past the end. This is why you end up going through the loop one extra time.

[seeplus]

Do you mean something like this:

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

void Data();
void Over_18(const std::string& ,int, char);
void Under_18(const std::string&, int);

int main() {
	Data();
}

void Data() {
	std::ifstream Main("Data.txt");

	if (Main) {
		int Age {};
		char Vote {};
		std::string Name;

		while (Main >> Name >> Age >> Vote)
			Age < 18 ? Under_18(Name, Age) : Over_18(Name, Age, Vote);
	} else
		std::cout << "Cannot open file\n";
}

void Under_18(const std::string& Name, int Age) {
	std::ofstream f18("Under 18.txt", std::ios::app);

	f18 << "Name: " << Name << '\n';
	f18 << "Age: " << Age << "\n\n";
}

void Over_18(const std::string& Name, int Age, char Vote) {
	std::ofstream f19("Over 18.txt", std::ios::app);

	f19 << "Name: " << Name << '\n';
	f19 << "Age: " << Age << '\n';
	f19 << "Vote: " << Vote << "\n\n";
}

This will read the input file and create the 2 output files as required.