Is it possible to pass cout or fout to a function?

c++ fstream ofstream
ChiefTwoPencils picture ChiefTwoPencils · Apr 27, 2012 · Viewed 23.7k times · Source

I'm trying to find a way to pass fout or cout to a function. I realize there are logically easy ways to deal with this, like put ifs in any function that outputs data or even just write the function both ways. However, that seems primitive and inefficient. I don't believe this code would ever work, I'm putting it here to ensure it's easy to see what I'd "like" to do. Please be aware that I'm taking a algorithm design class using c++, I'm in no way a seasoned c++ programmer. My class is limited to using the headers you see.

#include <iostream>
#include <iomanip>
#include <fstream>

using namespace std;
void helloWorld(char);
ofstream fout;

int main()
{
    fout.open("coutfout.dat");
    helloWorld(c);
    helloWorld(f);

    return 0;
}
void helloWorld(char x)
{
    xout << "Hello World";
    return;
}

Answer

Kevin Anderson picture Kevin Anderson · Apr 27, 2012

These both inherit from ostream so try this:

void sayHello(ostream& stream)
{
    stream << "Hello World";
    return;
}

Then in main, pass in the object (cout or whatever) and it should work fine.

Related questions

std::ofstream, check if file exists before writing

I am implementing file saving functionality within a Qt application using C++. I am looking for a way to check to see if the selected file already exists before writing to it, so that I can prompt a warning to …

Read More
do I need to close a std::fstream?

Possible Duplicate: Do I need to manually close a ifstream? Do I need to call fstream.close() or is fstream a proper RAII object that closes the stream on destruction? I have a local std::ofstream object inside a method. …

Read More
"Incomplete type not allowed " when creating std::ofstream objects

Visual Studio Throws this Strange Error: Incomplete type not allowed When I try to create an std::ofstream object. Here is the code I wrote inside a function. void OutPutLog() { std::ofstream outFile("Log.txt"); } whenever it encounters this Visual …

Read More