Writing Data to Files

[JonEngle]

Order of operation precedence: hours << day << endl; is equal to hours << (day << endl); You want: hours << day; hours << endl;

[Achim Klein]

The associativity of << is 'left to right'. So: hours << day << endl; is equal to (hours << day) << endl; Only the associativity of unary and assignment operators is 'right to left'. You can see it here. Regards Achim Klein

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We can do no great things, only small things with great love. - Mother Theresa

[Sweet Flame]

I changed it so that it reads: hours<

[Anonymous]

What's the class of your hours object ? Is it an ofstream ?

[Achim Klein]

And of which type is your day entity ? Is it just an int ?

---

We can do no great things, only small things with great love. - Mother Theresa

[Achim Klein]

Can you compile this ?

// --------
// Main.cpp
// --------
/**
* @file
* @brief Re: main()
* @version 0.1
*/

// --------
// Includes
// --------
#include <iostream>
#include <fstream>

// ---------------
// Used namespaces
// ---------------
using namespace std;

// -------------------------------
// Definition of the MyClass class
// -------------------------------
/**
* Foo.
*/
class MyClass
{

public:

// ------------
// Construction
// ------------

/// standard-constructor
MyClass();


// -------------
// Serialization
// -------------

/// writes the object to the passed stream
ostream& write(ostream& Stream) const;

private:

// ----------
// Attributes
// ----------

/// the first member
int m\_first;

/// the second member
int m\_second;

/// the third member
int m\_third;

};

// -------
// MyClass
// -------
/**
* The standard-constructor.
*/
MyClass::MyClass()
{
m_first = 1;
m_second = 2;
m_third = 3;
}

// -----
// write
// -----
/**
* Writes the object to the passed stream.
*/
ostream& MyClass::write(ostream& Stream) const
{
return Stream << "first : " << m_first << endl
<< "second : " << m_second << endl
<< "third : " << m_third;
}

// ----------
// operator<<
// ----------
/**
* ostream << MyClass
*/
ostream& operator<<(ostream& Stream, const MyClass& Object)
{
return Object.write(Stream);
}

// ----
// main
// ----
/**
* The application starts here.
*
* @param argc number of arguments
* @param argv list of arguments
*
* @return 0 if finished successfully
*/
int main(int argc, char** argv)
{
// ofstream cout("cout.txt");

cout << MyClass() << endl;

return 0;

}

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We can do no great things, only small things with great love. - Mother Theresa

[Sweet Flame]

yes, hours is an ofstream.

[Sweet Flame]

yes, my "day" is an int

[Sweet Flame]

yes, i can

[Achim Klein]

Maybe the compiler gets confused by your included header files. Try to use: <string> instead of <string.h> <fstream> instead of <fstream.h> <iostream> instead of <iostream.h> ... And avoid mixing them up.

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We can do no great things, only small things with great love. - Mother Theresa

[David Crow]

Something else is at play here. This works fine for me:

#include <fstream.h>

void main( void )
{
ofstream hours("c:\\file.txt");
int day = 20;
hours << day << endl;
}

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"Take only what you need and leave the land as you found it." - Native American Proverb

[Achim Klein]

Yes, this problem is really a bit strange... On my system the following code causes a C2679 error:

#include <string>
#include <fstream.h>

int main(int argc, char** argv)
{
ofstream hours("Hours.txt");

hours << "Hallo" << std::endl;

return 0;

}

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We can do no great things, only small things with great love. - Mother Theresa

[David Crow]

Writing string is different than writing int (your original problem). The ofstream class does not support writing string data. You have to provide that yourself:

#include <fstream>
std::ofstream &operator<<( std::ofstream &os, const std::string &str )
{
os << str.c_str();
return os;
}

---

"Take only what you need and leave the land as you found it." - Native American Proverb