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Need Help with programming

P: n/a
I am getting some error messages which I can't figure out their
meaning. I have the code setup, I think it's correct but it doesn't
work. My goal is to get this program to read from a data file and
basically put it into an output file that I can access as a test file.
Here is my header file:

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

struct StudRdType
{
int id;
float exam1;
float exam2;
float exam3;
};
StudRdType students;

void ReadRd(ifstream&, StudRdType[]);
void WriteRd(ofstream&, StudRdType[]);

Here is my function file: It is supposed to hit the data file, read it
and save the information. For example the data file looks like:

1111 275 323 432
1342 432 235 532
2343 235 432 234

So the ReadRd function is spoed to read that and save it. I can't get
it do that, im a bit rusty and can't seem to remember how to do this.
This is what I have for the function file (implementation).

#include "stud2.h"

void ReadRd(ifstream& inFile, StudRdType students[])

{

inFile.get(students.id);

while(inFile)
{
inFile >> students.exam1 >> students.exam2 >> students.exam3);
inFile.ignore('\n');
inFile.get(students.id);
}
}

void WriteRd(ofstream& outFile, StudRdType students[])
{
outFile << students.id << students.exam1 << students.exam2 <<
students.exam3 << endl;
outFile.setf(ios::fixed);
outFile.setf(ios::showpoint);
outFile.precision(2);
}

For some reason it isn't working , not sure hwy.. Finally here is my
driver file:

#include "stud2.h"

int main()
{

ifstream inFile;
ofstream outFile;
StudRdType students;
inFile.open("in.data");
outFile.open("out.data");
if(inFile.fail() || outFile.fail())
{
cout << "input or out file opening failed" << endl;
exit(1);
}

ReadRd(inFile, students);
WriteRd(outFile, students);

outFile << "*** END ***" << endl;

return 0;
}
Now here are the errors I get when I run them.. Again my goal is to
read the data file I showed above and print it to an outfile, the exact
same way as it looks.

Errors:

runstud2.cxx: In function `int main()':
runstud2.cxx:40: error: cannot convert `StudRdType' to `StudRdType*'
for
argument `2' to `void ReadRd(std::ifstream&, StudRdType*)'
runstud2.cxx:41: error: cannot convert `StudRdType' to `StudRdType*'
for
argument `2' to `void WriteRd(std:fstream&, StudRdType*)'
stud2.cxx: In function `void ReadRd(std::ifstream&, StudRdType*)':
stud2.cxx:15: error: request for member `id' in `students', which is of
non-class type `StudRdType*'
stud2.cxx:19: error: request for member `exam1' in `students', which is
of
non-class type `StudRdType*'
stud2.cxx:19: error: request for member `exam2' in `students', which is
of
non-class type `StudRdType*'
stud2.cxx:19: error: request for member `exam3' in `students', which is
of
non-class type `StudRdType*'
stud2.cxx:19: error: parse error before `)' token
stud2.cxx:21: error: request for member `id' in `students', which is of
non-class type `StudRdType*'
stud2.cxx: In function `void WriteRd(std:fstream&, StudRdType*)':
stud2.cxx:35: error: request for member `id' in `students', which is of
non-class type `StudRdType*'
stud2.cxx:35: error: request for member `exam1' in `students', which is
of
non-class type `StudRdType*'
stud2.cxx:35: error: request for member `exam2' in `students', which is
of
non-class type `StudRdType*'
stud2.cxx:35: error: request for member `exam3' in `students', which is
of
non-class type `StudRdType*'

I'm completely Confused.. I am in need of some serious help as I am
eager to learn this stuff and am unsure as to what I'm doing
incorrectly.

Thanks in advance!

Sep 16 '05 #1
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3 Replies


P: n/a
First up - I am NOT going to give you a correct working program (I
think you're having problems in your homework!)
#include <iostream.h>
#include <fstream.h>
#include <iomanip.h>
#include <iostream>
#include <fstream>
#include <iomanip>
Errors:
runstud2.cxx: In function `int main()':
runstud2.cxx:40: error: cannot convert `StudRdType' to `StudRdType*'
for
argument `2' to `void ReadRd(std::ifstream&, StudRdType*)'
This should tell you everything! You are passing an object where a
pointer is expected! All the other errors are also due to this very
mistake. In main, you've said -
StudRdType students;


This is a *single* object and *not* an array of objects. The functions
ReadRd and WriteRd are expecting pointers! Now, go figure it out how to
fix it - you've enough information to do it yourself!

Srini

Sep 16 '05 #2

P: n/a
Drewdog wrote:
I am getting some error messages which I can't figure out their
meaning. I have the code setup, I think it's correct but it doesn't
work.


LOL

You're confused about arrays, and are desparately trying to ignore this
issue in your code.

The easiest answer would be to use a vector instead of an array. But I'm
absolutely positive you won't want to take the easy route (newbies never
do).

So you need to get a C++ book and look up dynamic arrays, that is the
technique you need here.

Alternatively look up vectors. This will be easier in the long run but
mean that you have to throw away more of the code below.

john
Sep 16 '05 #3

P: n/a
On 9/15/2005 7:07 PM, Drewdog wrote:
struct StudRdType
{
int id;
float exam1;
float exam2;
float exam3;
};
StudRdType students;

void ReadRd(ifstream&, StudRdType[]);
void WriteRd(ofstream&, StudRdType[]);


If you look closely at your function prototypes, you will notice that
they are expecting to receive an array of StudRdType. The variable you
have defined calles "students" is not an array, it is mearly a variable
of type struct StudRdType. Turn that into an array and most of those
errors should disappear.

--
~Mushr00m Head
http://members.cox.net/mushroomhead/
Sep 16 '05 #4

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