CODEWITHSUNDEEP
c++text-filescoordinatesfile-io
Toemouse
Toemouse

Reputation: 40

Reading Co-ordinates from a Text File in C++

OK, so all I am trying to do is simply read some co-ordinates from a text file and use them to draw an array of bricks. I have this code:

ifstream infileScenario("scenario1.txt");

for (int i = 0; i < NUM_OF_BRICKS; i++)
{
    // read brick coordinates
    infileScenario >> bricks[i].m_x;
    infileScenario >> bricks[i].m_y;
    cout << bricks[i].m_x << "   " << bricks[i].m_y << endl;

    // set brick properties
    bricks[i].m_height = 0.1;
    bricks[i].m_width = 0.2;
    bricks[i].life = 3;
}

infileScenario.close();

But the only thing that I am getting printed to the console is a bunch of 0's. I've checked over my code again and again as well as double checking my text file and I still can't see where I am going wrong.

My text file is called scenario1.txt and it's contents are:

-0.6 0.7

-0.3 0.7

0 0.7

0.3 0.7

0.3 0.7

-0.6 0.5

-0.3 0.5

0 0.5

0.3 0.5

0.3 0.5

I wrote these values in myself which, if I had to hazard a guess, would think what could be causing my problem. Could it be to do with text encoding or am I wrong in thinking this?

Upvotes: 0

Views: 343

Answers (1)

phyrrus9
phyrrus9

Reputation: 1467

I would suggest not using the stream classes, they are a little more difficult to check for errors, here is the same code converted (with error checks) using fscanf.

FILE *infileScenario;
int i;

if ((infileScenario = fopen("scenario1.txt", "r")) == NULL) //didnt open readonly
{
    printf("Error, could not open scenario1.txt\n");
    exit(-1); //terminate program with a code we can read by running echo $?
}
for (i = 0; i < NUM_OF_BRICKS &&
            fscanf(infileScenario, "%lf %lf",
                   &bricks[i].m_x, &bricks[i].m_y) != EOF;
    i++)
{
    // read brick coordinates
    printf("%lf %lf\n", bricks[i].m_x, bricks[i].m_y);
    // set brick properties
    bricks[i].m_height = 0.1;
    bricks[i].m_width = 0.2;
    bricks[i].life = 3;
}

fclose(infileScenario);

You can also g++ -g -o and then gdb and run the following in gdb:

b main
r
s
(each time the for loop hits bricks[u].life = 3, run)
p bricks[i]
(otherwise, keep running)
s

That should allow you to diagnose what the issue seems to be, if my solution did not just fix it.

Upvotes: 1

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