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Please help with data file and array

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Join Date: Sep 2004

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christyj5

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Please help with data file and array

Oct 6th, 2005

I am trying to infile my data file into two seperate arrays which are seperated by a white space in my file.
But I keep getting -86******* something number where my file is suppose to be any help will be very helpful. My first array which will read the student id is a one dimensional array and the second arry is a 2 dimensional arry which will read in the students answers to a true false test and the second col will be the total number correct for each true false question. Yeah and the answer key is suppose to be the last line in the 2 D array which is the first line in my data file.

 Help with Code Tags 
 C++ Syntax (Toggle Plain Text) 
#include<iostream>
#include <fstream>
#include "string"
using namespace std;
int main()
{
    const int maxstudents=50;
	const int maxcols=3;
	char quiz[maxstudents+1][maxcols];
    int studentid[maxstudents];
 
	ifstream infile;
    string inputfile;
	cout<<"Input filename"<<endl;
	cin>> inputfile;
 
	infile.open(inputfile.c_str());
	for (int c = 0; c<maxstudents; c++)
		infile>>quiz[maxstudents][c]; 
		for (int k=0; k<maxstudents; k++)
			infile>>studentid[k];
 
		    for (int j=0; j<maxstudents; j++)
				cout<<"studentid"<<j<<"\t"<<studentid[j]<<endl;
              for (int r=0; r<10; r++)
	         cout<<quiz[maxstudents][r]<<"\t";
 
 
return 0;
}
#include<iostream>
#include <fstream>
#include "string"
using namespace std;
int main()
{
    const int maxstudents=50;
	const int maxcols=3;
	char quiz[maxstudents+1][maxcols];
    int studentid[maxstudents];

	ifstream infile;
    string inputfile;
	cout<<"Input filename"<<endl;
	cin>> inputfile;
	
	infile.open(inputfile.c_str());
	for (int c = 0; c<maxstudents; c++)
		infile>>quiz[maxstudents][c]; 
		for (int k=0; k<maxstudents; k++)
			infile>>studentid[k];
			
		    for (int j=0; j<maxstudents; j++)
				cout<<"studentid"<<j<<"\t"<<studentid[j]<<endl;
              for (int r=0; r<10; r++)
	         cout<<quiz[maxstudents][r]<<"\t";
           

return 0;
}

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Re: Please help with data file and array

Oct 6th, 2005

post the contents of the data file, or just a few lines if its too large. Your program is written to expect all student ids to be listed first, followed by all answers and lastly the total number correct for each student. But I doubt that is how they appear in the data file.

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christyj5

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Re: Please help with data file and array

Oct 6th, 2005

This is a piece of the data file.

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tttttttfft
ttftttttft
ttftfffttt
ttfffftttt
fftttffttt
fffffttttt
tttttttttf
tttttttttt
fffffffftt
tttttttfft
ttftttttft
ttftfffttt
ttfffftttt
fftttffttt
fffffttttt
tttttttttf
tttttttttt
fffffffftt

<< moderator edit: added code tags: [code][/code] >>

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Re: Please help with data file and array

Oct 6th, 2005

where is the third column? Your program needs only one loop. maxcols is too small -- needs to be 1 more than the number of t/f test scores.

 Help with Code Tags 
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for (int c = 0; c<maxstudents; c++)
{
	infile>>studentid[c] >> quiz[c]; 
}
for (int c = 0; c<maxstudents; c++)
{
	infile>>studentid[c] >> quiz[c]; 
}

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christyj5

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Re: Please help with data file and array

Oct 6th, 2005

i tried that and still got the -86 error

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Re: Please help with data file and array

Oct 6th, 2005

-86, is that a compile-time error or runtime error?
1. make sure maxstudents is not greater than the number of lines in the data file. There are better (and easier) ways to read the file without knowing the number of lines beforehand, but get this working first and you can refine your program later.

2. The output line is incorrect. It should look like this:

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cout<<quiz[r]<<"\t";
cout<<quiz[r]<<"\t";

If you still have problems after making the changes, repost your program. But those should fix it, at least it did in my version that I don't intend to post

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Re: Please help with data file and array

Oct 6th, 2005

 Help with Code Tags 
 C++ Syntax (Toggle Plain Text) 
#include<iostream>
#include <fstream>
#include "string"
 
using namespace std;
 
 
 const int maxstudents=25;
 
 
int main()
{
 
	const int maxcols=4;
    char quiz[maxstudents+1][maxcols];
    int studentid[maxstudents];
 
	ifstream infile;
    string inputfile;
	cout<<"Input filename"<<endl;
	cin>> inputfile;
 
	infile.open(inputfile.c_str());
 
 
for (int c = 0; c<maxstudents; c++)
{
	infile>> studentid[c] >> quiz[c]; 
}
 
for (int r=0; r<maxstudents; r++)
      cout<<quiz[r]<<"\t";	
return 0;
}
#include<iostream>
#include <fstream>
#include "string"

using namespace std;


 const int maxstudents=25;


int main()
{
   
	const int maxcols=4;
    char quiz[maxstudents+1][maxcols];
    int studentid[maxstudents];

	ifstream infile;
    string inputfile;
	cout<<"Input filename"<<endl;
	cin>> inputfile;
	
	infile.open(inputfile.c_str());
       

for (int c = 0; c<maxstudents; c++)
{
	infile>> studentid[c] >> quiz[c]; 
}

for (int r=0; r<maxstudents; r++)
      cout<<quiz[r]<<"\t";	
return 0;
}

<< moderator edit: added code tags: [code][/code] >>

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Re: Please help with data file and array

Oct 6th, 2005

const int maxcols=4;

Count the number of t's and f's in one of those lines. How many did you count? Less than 4 or more than 4. maxcols needs to be a minimum of (number of t's and f's) + 1 for the character array's null-terminator.

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christyj5

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Re: Please help with data file and array

Oct 6th, 2005

I am getting a blank page

 Help with Code Tags 
 C++ Syntax (Toggle Plain Text) 
#include<iostream>
#include <fstream>
#include "string"
 
using namespace std;
 
 
 const int maxstudents=3;
int main()
{
 
 
	ifstream infile;
    string inputfile;
	cout<<"Input filename"<<endl;
	cin>> inputfile;
 
	infile.open(inputfile.c_str());
 
 
	char quiz[maxstudents+1][11];
    int studentid[maxstudents];
 
for (int c = 0; c<maxstudents; c++)
{
infile>> studentid[c] >> quiz[c]; 
}
 
for (int r=0; r<maxstudents; r++)
cout<<quiz[r]<<"\t"; 
return o;
}
#include<iostream>
#include <fstream>
#include "string"

using namespace std;


 const int maxstudents=3;
int main()
{
   
	
	ifstream infile;
    string inputfile;
	cout<<"Input filename"<<endl;
	cin>> inputfile;
	
	infile.open(inputfile.c_str());
 

	char quiz[maxstudents+1][11];
    int studentid[maxstudents];
	
for (int c = 0; c<maxstudents; c++)
{
infile>> studentid[c] >> quiz[c]; 
}

for (int r=0; r<maxstudents; r++)
cout<<quiz[r]<<"\t"; 
return o;
}