Incorrectly returning a value from a function in C++

Question

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Code:

 int main () { ifstream inStream; ofstream outStream; getInputOutputStreams(inStream, outStream); numberFile(inStream, outStream); return EXIT_SUCCESS; }

I have been stuck with an issue where the code I wrote compiles, but when running it has to be terminated because it just lags. I believe my issue may have to deal with not correctly returning the names of the input and output files, but I cannot figure out where I'm going wrong. I'm only a beginner in C++ (we are just now learning about arrays), so if you think this is a dumb question I'm sorry!

Here is the code I have written:

#include <iostream>
#include <cstdlib>
#include <fstream>
#include <string>

using namespace std;

string getInputOutputStreams(ifstream &inStream, ofstream &outStream);

void numberFile(ifstream &inStream, ofstream &outStream);

int main ()
{
    ifstream inStream;

    ofstream outStream;
    getInputOutputStreams(inStream, outStream);

    numberFile(inStream, outStream);

    return EXIT_SUCCESS;
}

string getInputOutputStreams(ifstream &inStream, ofstream &outStream)
{
    string inputFile;
    string outputFile;

    cout << "Enter the name of the input file:" << endl;
    cin >> inputFile;
    inStream.open(inputFile);

    while (inStream.fail()) {
        cout << "Invalid file name." << endl;
        cout << "Enter the name of an input file:" << endl;
        cin >> inputFile;
        inStream.open(inputFile);
    }
    inStream.close();

    cout << "Enter the name of the output file:" << endl;
    cin >> outputFile;
    outStream.open(outputFile);

    while (outStream.fail()) {
        cout << "Invalid file name." << endl;
        cout << "Enter the name of an output file:" << endl;
        cin >> outputFile;
        outStream.open(outputFile);
    }
    outStream.close();

    return inputFile;
    return outputFile;
}

void numberFile(ifstream &inStream, ofstream &outStream)
{
    string inputFile;
    string outputFile;

    inStream.open(inputFile);
    outStream.open(outputFile);

    int lineNumber = 0;
    string line;

    while(!inStream.eof()) {
        if(line == " ") {
        }
        else {
            lineNumber++;
            outStream << lineNumber << ": " << line << endl;
        }

        getline(inStream, line);
    }

    cout << lineNumber << " lines processed" << endl;

    inStream.close();
    outStream.close();
}

Answer 1

I see a number of mistakes:

1. getInputOutputStreams() is closing the streams that it opens.

2. incorrect return statements in getInputOutputStreams() .

3. numberFile() is re-opening the streams, using filename strings that have no values.

4. using while(!inStream.eof()) is bad .

5. not ignoring blank lines, as the instructions ask for.

Try this instead

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

void getInputOutputStreams(ifstream &inStream, ofstream &outStream);

void numberFile(ifstream &inStream, ofstream &outStream);

int main ()
{
    ifstream inStream;
    ofstream outStream;

    getInputOutputStreams(inStream, outStream);
    numberFile(inStream, outStream);

    return EXIT_SUCCESS;
}

void getInputOutputStreams(ifstream &inStream, ofstream &outStream)
{
    string inputFile;
    string outputFile;

    cout << "Enter the name of the input file:" << endl;
    cin >> inputFile;
    inStream.open(inputFile);

    while (inStream.fail()) {
        cout << "Invalid file name." << endl;
        cout << "Enter the name of an input file:" << endl;
        cin >> inputFile;
        inStream.open(inputFile);
    }

    cout << "Enter the name of the output file:" << endl;
    cin >> outputFile;
    outStream.open(outputFile);

    while (outStream.fail()) {
        cout << "Invalid file name." << endl;
        cout << "Enter the name of an output file:" << endl;
        cin >> outputFile;
        outStream.open(outputFile);
    }
}

void numberFile(ifstream &inStream, ofstream &outStream)
{
    int lineNumber = 0;
    string line;

    while (getline(inStream, line)) {
        if (line != "") {
            ++lineNumber;
            outStream << lineNumber << ": " << line << endl;
        }
    }

    cout << lineNumber << " lines processed" << endl;
}