Hello all,

I have a text file set up as follows.

1 1 1
2 2 2

The program below is not reading the first line. The code below will only read 2 2 2. What am I missing here?


main.cpp

#include <iostream>
#include <limits>
#include <cmath>
#include <cstdlib>
#include <cstddef>
#include <fstream>
#include <cctype>
#include <ctime>
#include <string>
#include <iomanip>
#include <queue>
using namespace std;#include "utility.h"
#include "Graph.h"
int main()
{
	Graph g;

	g.load_graph("GraphDemo1.txt");


}

Graph.h

#ifndef KEY_H
#define KEY_H

#include "utility.h"

class Graph
{
public:
	Graph();
	void load_graph(string fileName);


private:
	int graph_size;
	int matrix[25][25];
};

Graph::Graph()
{

}

void Graph::load_graph(std::string fileName)
{
	ifstream fin(fileName.c_str());
	if (!fin.is_open())
	{
		cout << endl << "Unable to open input file" << fileName	<< endl;
	}

	graph_size = 0;
	while(getline(fin,fileName))
	{
		for(int i = 0; i < 3; i++)
		{
			fin >> matrix[graph_size][i];
			cout << "graph: " << graph_size << " i: " << i << "   " << matrix[graph_size][i] << endl;
			
		}
		//cout << graph_size << endl;
		graph_size++;

	}
}


#endif //KEY_H

I changed lines 32-43 to a "do-while loop" instead of a "while loop" and it works.

Initially, I thought the "fin" in line 23 might be tripping the first line, and making me skip over it. But this logic does not make sense, because it would seem like I would miss the second line with the code below, but I don't. So I am not sure why the "do-while loop" works?

do
	{
		for(int i = 0; i < 3; i++)
		{
			fin >> matrix[graph_size][i];
			cout << "graph: " << graph_size << " i: " << i << "   " << matrix[graph_size][i] << endl;
			
		}
		//cout << graph_size << endl;
		graph_size++;

	}while(getline(fin, fileName));

What does line 32 do?

Doesn't "getline(fin,fileName)" return true if there is another line, and false if we're at the end of the file?

I've been playing around with this. Now, instead of getline(), I am using good().

My text file now looks like this

A 12 7
A 45 3
A 13 6
D
A 19 8
D
D

The program is stopping on line 4. What do I need to change so the program pulls in the entire file?

#include "utility.h"
#include "message.h"
#include "pQueue.h"

int main()
{	int test = 0;
	string fileName = "lab10pqDemo.txt";

	// Test file availabilty
	ifstream fin(fileName.c_str());
	if (!fin.is_open())
	{
		cout << endl << "Unable to open input file" << fileName	<< endl;
	}

	// Load file into pQueue
	string status;
	int data;
	int priority;
	pQueue<message> messageQueue;
	do
	{
		fin >> status;
		fin >> data;
		fin >> priority;	

		cout << "test: " << test << " status: " << status << " data: " << data << " priority: " << priority << endl;
/*	
		if(status == "A")
		{
			message m;
			m.create_message(status, data, priority);
			messageQueue.push(m);
		}
*/	

	}while(fin.good());
	//}while(getline(fin, fileName));



}

Figured out a solution...

#include "utility.h"
#include "message.h"
#include "pQueue.h"

int main()
{	int test = 0;
	string fileName = "lab10pqDemo.txt";

	// Test file availabilty
	ifstream fin(fileName.c_str());
	if (!fin.is_open())
	{
		cout << endl << "Unable to open input file" << fileName	<< endl;
	}

	// Load file into pQueue
	string status;
	int data;
	int priority;
	pQueue<message> messageQueue;
	do
	{
		fin >> status;

		if(status == "A")
		{		
			fin >> data;
			fin >> priority;	
		}
		else
		{
			data = NULL;
			priority = NULL;
		}

		cout << "test: " << test << " status: " << status << " data: " << data << " priority: " << priority << endl;
/*	
		if(status == "A")
		{
			message m;
			m.create_message(status, data, priority);
			messageQueue.push(m);
		}
*/	

	}while(fin.good());
	//}while(getline(fin, fileName));



}
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