C++ reading data from file into array

[tlcvetan158]

Hi, I'm a newbie at C++. I am just trying to read a file with three columns of data into arrays and write it back out, to see how arrays work.

This runs with no errors, but the output doesn't look like the input, so I think I just have something specified incorrectly, but not sure what.

My input:
1999 1 3
1999 2 6
1999 4 5

My program:

#include <fstream>
#include <iostream>
#include <iomanip>
#include <cstdlib>
using namespace std;

void OpenFile(ifstream& fin);

void OpenFile(ofstream& fout);

void getInput(ifstream& fin,
int year[],
int month[],
int rain_in_month[]);

int main()
{
using namespace std;

//Variable declarations
const int MONTHS_IN_FILE = 36; //three years of data in file
int year[MONTHS_IN_FILE];
int month[MONTHS_IN_FILE];
int rain[MONTHS_IN_FILE];
ifstream fin; //naming the input file for the program
ofstream fout; //naming the output file for the program


fout.setf(ios::fixed);
fout.setf(ios::showpoint);
fout.precision(1);

//Open the input file
fin.open("rainInput2.txt");
OpenFile(fin);

//Open the output file
fout.open("rainOutput2.txt");
OpenFile(fout);

//Process the records from the input file until the end of file is reached
while (!fin.eof())
{
//Read the input file
getInput(fin, year, month, rain_in_month);

}
for (int i=0; i < MONTHS_IN_FILE; i++)
cout << year[i] << month[i] << rain_in_month[i] << endl;

//Close the input and output files
fin.close();
fout.close();
} // End function main

void OpenFile(ifstream& fin)
{
if (fin.fail())
{
cout<< "Input file opening failed.\n";
exit(1);
}
} // End function OpenFile

void OpenFile(ofstream& fout)
{
if (fout.fail())
{
cout<< "Output file opening failed.\n";
exit(1);
}
} // End function OpenFile

void getInput(ifstream& fin, int year[], int month[], int rain_in_month[])
{
int i = 0;
fin >> year[i] >> month[i] >> rain_in_month[i];
i++;
cout << year[i] << month[i] << rain_in_month[i] << endl;

return;

} // End function getInput

[tyreld]

Please don't double post.

What does your output look like?

[tlcvetan158]

I did not mean to double post some how it hit enter before I was done and I could not find the icon to delete one of them.

this is the output - minus some of the same lines for space:

-858993460-858993460-9.25596e+061
-858993460-858993460-9.25596e+061
-858993460-858993460-9.25596e+061
-200276
-858993460-858993460-9.25596e+061
-858993460-858993460-9.25596e+061
-858993460-858993460-9.25596e+061
Press any key to continue . . .

[rahvege]

Your not passing your arrays in my reference.

[iknc4miles]

//Process the records from the input file until the end of file is reached
while (!fin.eof())
{
//Read the input file
getInput(fin, year, month, rain_in_month);

}
...
...
...

void getInput(ifstream& fin, int year[], int month[], int rain_in_month[])
{
int i = 0;
fin >> year[i] >> month[i] >> rain_in_month[i];
i++;
cout << year[i] << month[i] << rain_in_month[i] << endl;

return;

}

This is probably not the problem you're having, but your getInput function within the while loop keeps initialize i to 0 so all your values are stored at (array)[0]. You then advance i by one to a value in your year, month, and rain_in_month arrays that is not defined and try to output it.

Try rewriting the code like this and see if it helps:

getInput(fin, year&, month&, rain_in_month&);
...
...
...
void getInput(ifstream fin, int &year, int &month, int &rain_in_month)
{
    int i = 0;
        while(!fin.eof())
        {
       fin >> &year[i] >> &month[i] >> &rain_in_month[i];
       cout << year[i] << month[i] << rain_in_month[i] << endl;
           i++;
        }
 
    return;
 
}

I'm fairly new to C++ myself so I might have the pointers a bit screwed up. This way, you call getInput and it grabs all your data, assigns it to your arrays at the correct locations, and then outputs to the console what it saved.

- Miles