CODEWITHSUNDEEP
c++
user1708753
user1708753

Reputation:

Call by reference-stream and char in c++

My latest homework assignment is to write a program that reads a textfile and outputs the number of lines, words and characters.

I'm just starting out, all I'm trying to do right now is to let the user type in the file name and then the file will open. This is my not-working code, I must be missing something obvious, I'm just trying to pass the stream and char to the 'input' function.

Any pointers?

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

//Define functions.
void input(ifstream& fin, char& fileName);

int main()
{
    ifstream fin;
    char fileName[20];
    input(fin, fileName);
    return 0;
}

void input(ifstream& fin, char& fileName)
{
    cout << "Input file name: ";
    cin >> fileName;
    fin.open(fileName);

    if(fin.fail())
    {
        cout << "The file:  " << fileName << " does not open." << endl;
        exit(1);
    }
    //return;
}

Upvotes: 0

Views: 241

Answers (4)

Ujjwal Singh
Ujjwal Singh

Reputation: 4988

your input function's second param: char& fileName is a reference to a char; whereas - what you need is a reference to an array of 20 chars

Thus, change it to: void input(ifstream& fin,char (&fileName)[20])

Upvotes: 0

Jessel A. Sancho
Jessel A. Sancho

Reputation: 1

Your syntax isn't correct. Use:

void input(ifstream *fin, char *fileName);

And:

input(&fin, &fileName); // call

Here you are passing the reference of the variable to the pointer (*).

Make the required changes and it should work fine.

Upvotes: 0

Bo Persson
Bo Persson

Reputation: 92271

One problem is that char& is a reference to a single char, not an array or a string.

This will work much better if you use std::string fileName, and pass a string& parameter around.

Upvotes: 0

WhozCraig
WhozCraig

Reputation: 66224

This will probably get you closer. At least past your compilation errors, but you still need work on a few things. Get thee to a reference manual and a debugger.

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

//Define functions.
void input(ifstream& fin, string& fileName);

int main()
{
    ifstream fin;
    string fileName;
    input(fin, fileName);
    return 0;
}

void input(ifstream& fin, string& fileName)
{
    cout << "Input file name: ";
    cin >> fileName;
    fin.open(fileName.c_str());

    if(fin.fail())
    {
        cout << "The file:  " << fileName << " does not open." << endl;
        exit(1);
    }
    //return;
}

Not the way I'd do this, but you gotta learn sometime. Good luck!

Upvotes: 1

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