Trouble reading data form text file into array

Question

My program is not printing what i want it to print.

#include<cstdlib>
#include<cmath>
#include<fstream>
#include<sstream>
#include<iomanip>
#include<iostream>
#include<string>
#include<cstring>
#include<cassert>
#include<ctime>
#include<cctype>
#include<algorithm>
#include<locale.h>
#include<stdio.h>
#include<functional>
#include<math.h>

using namespace std;

int main(int argc, char**argv)
{
    int r = 0;
    int p = 0;
    int c = 0;
    string names[20];
    double scores[20][10];

    ifstream infile;
    infile.open("C:\\Users\\Colin\\Documents\\NetBeansProjects\\Bowlerspart2\\data\\bowlers.txt");

    while(!infile)
    {
        cout << "can not find file" << endl;
        return 1;
    }

    for(r = 1; r <= 10; r++)
    {
        getline(infile, names[r]);
        for(c = 1; c <= 3; c++)
        {
            infile >> scores[r][c];
        }
    }

    infile.close();

    for(r = 1; r <= 10; r++)
    {
        cout << names[r] << endl;
        cout << fixed << setprecision(2) << endl;
        cout << scores[r][c] << endl;
    }

    return 0;
}

It only prints one of the names and prints 0.00 for all the scores. I believe I'm probably reading the file wrong, but not sure how.

Here is the text file:

Linus too good
100
23
210
Charlie brown
1
2
12
Snoopy
300
300
100
Peperment Patty
223
300
221
Pig Pen
234
123
212
Red Headed Girl
123
222
111
Marcey
1
2
3
Keith hallmark
300
300
250
Anna hallmark
222
111
211
Roxie hallmark
100
100
2

this is the output I get with my code:

Linus too good

0.00


0.00


0.00


0.00


0.00


0.00


0.00


0.00


0.00


0.00

The output is followed by multiple blank lines if I comment out the printing of the scores array. I manipulated the parameters of the for loops and nothing seems to work right. Could someone point me in the right direction?

Your loops look 1 based instead of 0 based. Remember c++ array indices are 0 .. size-1 not 1 ..size. With that said this does not appear to have caused your issue. — drescherjm
– drescherjm, Commented Oct 15, 2017 at 20:22
You may want to change while(!infile) to if (!infile). The loop only performs one iteration because of the return statement. — Thomas Matthews
– Thomas Matthews, Commented Oct 15, 2017 at 20:25
As a side-note you only need these headers: <iostream>, <string>, <fstream> and <iomanip>. — Ron
– Ron, Commented Oct 15, 2017 at 20:25
@ThomasMatthews I changed the 'while(!infile)' to 'if(!infile)' and it didn't change anything, but I do see your point. — Misplaced Southerner
– Misplaced Southerner, Commented Oct 15, 2017 at 20:42

Barmak Shemirani · Accepted Answer · 2017-10-15 21:59:22Z

1

for(c = 1; c <= 3; c++)
{
    infile >> scores[r][c];
}

You expect to have one integer on a single line. Read the whole line and convert to double:

for(c = 1; c <= 3; c++)
{
    string temp;
    getline(infile, temp);
    scores[r][c] = std::stod(temp);
}

Your print function keeps printing the same scores[r][c] which stores the initialization value (zero in this case). You forgot to loop through the value like this:

for(r = 1; r <= 10; r++)
{
    cout << names[r] << endl;
    cout << fixed << setprecision(2) << endl;
    for (c = 1; c <= 3; c++)
        cout << scores[r][c] << endl;
}

Note that scores[r][c] = std::stod(temp); needs exception handling if temp cannot be converted to double.

try
{
    scores[r][c] = std::stod(temp);
}
catch(...)
{
    //add error handling
}

You can add additional error handling and start at zero index as suggested in comments

#include <iostream>
#include <fstream>
#include <iomanip>
#include <string>
...

for(int r = 0; r < 10; r++)
{
    if(!getline(infile, names[r]))
        break;
    for(int c = 0; c < 3; c++)
    {
        string temp;
        if(!getline(infile, temp))
            break;
        try
        {
            scores[r][c] = std::stod(temp);
        }
        catch(...)
        {
        }
    }
}

for(int r = 0; r < 10; r++)
{
    cout << names[r] << endl;
    cout << fixed << setprecision(2) << endl;
    for (int c = 0; c < 3; c++)
        cout << scores[r][c] << endl;
}

edited Oct 15, 2017 at 21:59

answered Oct 15, 2017 at 20:53

Barmak Shemirani

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1 Comment

Misplaced Southerner Over a year ago

Thank you! 2 days of no results and it was this simple.

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