Getting data from TXT file...

[xxeddiexx]

This is the TXT file:


NORTH-SOUTH road
2 4 6 8 0 3 5 7 9 8 6 4 2 -4 -6 -8 -2 0 -6 -8 -3 1 3 5 7 0 0 11 8 4 1 -3 2 9 4 6 2 0 -7 -9 -5 -4 -2 3 8 7 1 -9 -5 -3 -8 -9 1 3 5 7 9 12 13 7 5 2 0 -2 -999
WEST-EAST road
3 5 7 0 0 11 8 4 1 -3 2 2 0 -7 -9 -5 -4 -2 3 8 7 1 -9 -5 9 8 6 4 -2 0 -6 -8 -3 1 3 5 7 0 0 14 8 4 1 -3 2 6 4 2 -4 -6 -8 -2 0 -6 -8 -999


I need to input the integers only into two arrays, let's call them RoadNS[?] and RoadWE[?].
When it reads the file it should 'skip' the letters 'NORTH-SOUTH road', input the integers {2, 4, 6, 8, 0.....} into array RoadNS[?], terminate when it sees the first '-999', then again 'skip' the letters 'WEST-EAST road', input the rest of the integers {3, 5, 7, 0, ......} into array RoadWE[?], and terminate at '-999'.
My problem is that I don't know how to skip the letters, then resume and start inputing the integers into an array, then terminate at -999 and again skip the letters and input the rest of the integers...
I CAN ONLY USE SIMPLE ARRAYS, FOR LOOPS, DO/WHILE LOOPS, FUNCTIONS AND CLASSES. NO SPECIAL ARRAYS ETC, I'M ONLY A BEGINNER

Please help

[CornedBee]

Have you deleted the old thread? You should leave it there, for someone to search for information applicable to his/her own problem.

The exercise interested me, I have written a program that does just that. I will not post it, only use it for my own reference.

The code I used is quite complicated. I basically did the following:
1) Read one line of the text file into a string buffer.
2) Check if the line contains the word "road".
3) If yes, start over.
4) Else read in integers until you hit -999 or there are no more integers in the line.
5) Start over.

Just to give you a taste, here are the header files my app includes + the using declarations:

#include <iostream>
#include <sstream>
#include <fstream>
#include <string>
#include <vector>
#include <algorithm>
#include <iterator>
#include <functional>
using std::string; // <string>
using std::ifstream; // <iostream>
using std::istringstream; // <sstream>
using std::cout; // <iostream>
using std::endl; // <iostream>
using std::vector; // <vector>
using std::getline; // <string>
using std::copy; // <algorithm>
using std::max_element; // <algorithm>
using std::min_element; // <algorithm>
using std::count_if; // <algorithm>
using std::ostream_iterator; // <iterator>
using std::unary_function; // <functional>

[xxeddiexx]

My 16-year old friend figured out how to do this. Here's the code he used:

{
ifstream fin("assign_07_in.txt");
if (!fin.is_open())
exit(1);

int RoadNS[70] = { 0 };
int RoadWE[70] = { 0 };

fin.ignore(100, '\n');
int temp_input;
int i = 0;
while (fin >> temp_input && temp_input != -999)
{
RoadNS[i] = temp_input;
i++;
}
fin.get();
i = 0;
fin.ignore(100, '\n');
while (fin >> temp_input && temp_input != -999)
{
RoadWE[i] = temp_input;
i++;
}
fin.close();
}

[parksie]

int RoadNS[70] = { 0 };

What happens when your teacher decides to test your program by giving more than 70 numbers?

[CornedBee]

Ok, you have working code for reading in. Now here's mine:

#include <iostream>
#include <sstream>
#include <fstream>
#include <string>
#include <vector>
using std::string;
using std::ostream;
using std::ifstream;
using std::istringstream;
using std::cout;
using std::endl;
using std::vector;
using std::getline;

const int NUM_ROADS = 2;

bool parseline(vector<int> &road, const string &line);

void main()
{
	cout << "Reading file" << endl;
	ifstream ifs("streets.txt");
	string line;
	int i=0;
	vector<int> roads[NUM_ROADS];
	while(!ifs.eof())
	{
		getline(ifs, line);
		if(parseline(roads[i], line))
			++i;
	}
}

bool parseline(vector<int> &road, const string &line)
{
	int temp=0, start;
	if(line.find("road") == string::npos)
	{
		istringstream iss(line);
		iss >> start;
		road.push_back(start);
		while(!iss.eof() && temp != -999)
		{
			iss >> temp;
			road.push_back(start+temp);
		}
		if(temp == -999)
		{
			road.pop_back();
			temp = 0;
			return true;
		}
	}
	return false;
}

Independent of the number of roads and of the number of points per road. And it automatically handles the relative heights.

For your code: how do you know how many elements were read for the arrays? You don't save that...

[xxeddiexx]

int RoadNS[70] = { 0 }
What happens when your teacher decides to test your program by giving more than 70 numbers?
__________________

why? what do you think would happen?

[parksie]

Well, what do you think? There's only space for 70 in there, so when you add the 70th item (indexes from 0, remember), where does it go?

The answer is, most likely on top of whatever's defined next. This can cause all sorts of amusing bugs.

[xxeddiexx]

For your code: how do you know how many elements were read for the arrays? You don't save that...
__________________

That's what I said so I've modified the code a little bit myself. Here's my final version:

int RoadNS[70] = { 0 };
int RoadWE[70] = { 0 };

fin.ignore(100, '\n');
int temp_input;
int x = 0, y = 0;
while (fin >> temp_input && temp_input != -999)
{
RoadNS[x] = temp_input;
x++;
}
fin.get();
fin.ignore(100, '\n');
while (fin >> temp_input && temp_input != -999)
{
RoadWE[y] = temp_input;
y++;
}
fin.close();

That will give me the size of both arrays in x and y.

[xxeddiexx]

Well, what do you think? There's only space for 70 in there, so when you add the 70th item (indexes from 0, remember), where does it go?

The answer is, most likely on top of whatever's defined next. This can cause all sorts of amusing bugs.
__________________

Ohh, you're right, of course it would cause a problem. However, in my homework we don't have to worry about it so I just counted the numbers manually Remember, we're just starting to cover Arrays...

[parksie]

I'd say go with CB's method of using a vector. That's what they're there for, and if your teacher/course says different they're an imbecile (and yes, you can tell them I said that and where to find me... )

[xxeddiexx]

I'd say go with CB's method of using a vector. That's what they're there for, and if your teacher/course says different they're an imbecile (and yes, you can tell them I said that and where to find me... )
______________

You don't know how much I agree with you parksie...

Just in case you're interested, my teacher assistant (not the professor) finally decided to give me a hint... This is how they want us to do it:


int RoadNS[70], RoadWE[70], a, b;
a = 0;
b = 0;

Declare a character variable here.
fin.get(character variable);
while(character != newline character)
fin.get(character variable);

fin >> RoadNS[a];
while (RoadNS[a] != -999)
{
a++;
fin >> RoadNS[a];
}

fin.get(character variable);
while(character != newline character)
fin.get(character variable);

fin >> RoadWE[b];
while (RoadWE[b] != -999)
{
b++;
fin >> RoadWE[b];
}


I haven't tried it yet, but from just looking at it do you think it would work?

[CornedBee]

Yes, except that it doesn't take into account the relative heights.