Reading txt file into 2d array C++

Question

I know this question has been asked before, but I cannot seem to find an answer to my particular problem. I am reading in txt file.

weather.txt

1 52 32

2 54 32

3 54 30

4 48 28

5 37 25

6 37 25

7 46 34

8 55 45

9 59 46

10 61 37

11 55 32

12 59 34

There is more data but for space sake I put this.

I am trying to read into the array 0,0 1,0 2,0 then it will go to 0,1 1,1 2,1 then 0,2 1,2 2,2. Just repeating the rows. With the code I have now it just gets stuck. and the output looks like this....

Location: 0 : 0 Data in textFile: 1 Location: 1 : 0 Data in textFile: 1 Location: 2 : 0 Data in textFile: 1 Location: 0 : 1 Data in textFile: 1 Location: 1 : 1 Data in textFile: 1 Location: 2 : 1 Data in textFile: 1 Location: 0 : 2 Data in textFile: 1 Location: 1 : 2 Data in textFile: 1 Location: 2 : 2 Data in textFile: 1 Location: 0 : 3 Data in textFile: 1 Location: 1 : 3 Data in textFile: 1 Location: 2 : 3 Data in textFile: 1 Location: 0 : 4 Data in textFile: 1 Location: 1 : 4 Data in textFile: 1 Location: 2 : 4 Data in textFile: 1 Location: 0 : 5 Data in textFile: 1 Location: 1 : 5 Data in textFile: 1 Location: 2 : 5 Data in textFile: 1 Location: 0 : 6 Data in textFile: 1 Location: 1 : 6 Data in textFile: 1 Location: 2 : 6 Data in textFile: 1 Location: 0 : 7 Data in textFile: 1 Location: 1 : 7 Data in textFile: 1 Location: 2 : 7 Data in textFile: 1 Location: 0 : 8 Data in textFile: 1 Location: 1 : 8 Data in textFile: 1 Location: 2 : 8 Data in textFile: 1 Location: 0 : 9 Data in textFile: 1 Location: 1 : 9 Data in textFile: 1 Location: 2 : 9 Data in textFile: 1 Location: 0 : 10 Data in textFile: 1 Location: 1 : 10 Data in textFile: 1

It goes through the whole file but restarting back to 0,0.

Location: 0 : 0 Data in textFile: 52

Location: 1 : 0 Data in textFile: 52

Location: 2 : 0 Data in textFile: 52

Any help would be appreciated sorry for all the text just trying to be as clear as possible.

#include <iostream>
#include <fstream>

using namespace std;

int main() {

int width = 31;//declaring days or columns for array
int height = 3;//declaring information day and high and low
int data;

/* Code to read in txt file */
ifstream infile;
infile.open("weather.txt");

if (!infile) {
    cerr << "Unable to open file  C\n";
    exit(1);   // call system to stop
}
/* end code read text file */

 int tempDay[height][width];

  //PROBLEM WITH LOOP//
while (infile >> data) {
    for (int i = 0; i < width; ++i) {
        for (int j = 0; j < height ; ++j) {
        tempDay[j][i] = data;
 cout << "Location: " << j <<" : " << i << " Data in textFile: " <<data<<endl;
        }
     }

}

infile.close();
return 0;     
}

From your example, seems like height = 31 and width = 3, but you show code in reverse. Also, did you notice that you have three loops, the while and the two fors.. Think about this and fix it. — Khalil Khalaf
– Khalil Khalaf, Commented Apr 21, 2017 at 3:41

kabdulla · Accepted Answer · 2017-04-21 04:22:56Z

The following should work provided the text file is as described and there are any unexpected characters. It is similar to your code except it checks for an unexpected end-of-file (i.e. if there aren't WIDTH rows in the file) within the for loop.

#include <iostream>
#include <fstream>
#include <cstdlib>

using namespace std;

int main() {

const int WIDTH = 31;//declaring days or columns for array
const int HEIGHT = 3;//declaring information day and high and low

/* Code to read in txt file */
ifstream infile;
infile.open("weather.txt");

if (!infile) {
    cerr << "Unable to open file\n" << endl;
    exit(1);   // call system to stop
}
/* end code read text file */

int tempDay[HEIGHT][WIDTH];

for (int i = 0; i < WIDTH; ++i) {
    for (int j = 0; j < HEIGHT ; ++j) {
        if (!(infile >> tempDay[j][i])) {
            cerr << "Unexpected end of file\n" << endl;
            exit(1);   // call system to stop
        }
        cout << "Location: " << j <<" : " << i << " Data in textFile: " << tempDay[j][i] << endl;
    }
}

infile.close();
return 0;     
}

Khalil Khalaf · Accepted Answer · 2017-04-21 03:48:41Z

0

Since you know the sizes, this should work:

const int width = 3;//declaring days or columns for array
const int height = 31;//declaring information day and high and low

// .. 

int tempDay[height][width];

// ..

int i = 0;
while (infile >> tempDay[i][0] >> tempDay[i][1] >> tempDay[i][2]) // one line at a time
{
    cout << tempDay[i][0] << ' ' << tempDay[i][1] << ' ' << tempDay[i][2] << endl;
    i++;
}

answered Apr 21, 2017 at 3:48

Khalil Khalaf

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