error: 'ostream' has not been declared

[wyndz0108]

hello,
i have this program that prints out some text using ostream. i am
using g++ (GCC) 3.4.4; the original program compiles and run. refer to
first program below.
but when i modified it by moving the class to a header file, i
encountered an error. refer to second program below.
can somebody help?


// start of original program
#include <fstream>
#include <iostream>

using namespace std;

class outC {
public:
void display (ostream& out) { out << "testing 1, 2, 3" << endl;}

};

int main (int argc, char * argv) {
ofstream outfile;
outfile.open("out.tmp");

outC my;
my.display(outfile);

outfile.close();
return 0;
}

// end of original program

modified program with 2 files (main and header files)

//start of main file (modified program)
#include <fstream>
#include <iostream>
#include "out.h"

using namespace std;

int main (int argc, char * argv) {
ofstream outfile;
outfile.open("out.tmp");

outC my;
my.display(cout);

outfile.close();
return 0;
}

void outC::display (ostream& out) {
out << "testing 1, 2, 3" << endl;
}

// end of main file (modified program)


//start of header file (for the modified program)
#ifndef OUTH
#define OUTH

class outC {
public:
void display (ostream& out);

};

#endif

// end of header file (for the modified program)

 

[Steve.M.Brain]

Hi,

the most likely reason it wont compile is that your

using namespace std;

line should be above the
#include "outC.h" header
(or in the outC.h file itself)

 

[Salt_Peter]

hello,
i have this program that prints out some text using ostream. i am
using g++ (GCC) 3.4.4; the original program compiles and run. refer to
first program below.
but when i modified it by moving the class to a header file, i
encountered an error. refer to second program below.
can somebody help?

// start of original program
#include <fstream>
#include <iostream>

using namespace std;

class outC {
public:
void display (ostream& out) { out << "testing 1, 2, 3" << endl;}

};

int main (int argc, char * argv) {
ofstream outfile;
outfile.open("out.tmp");

outC my;
my.display(outfile);

outfile.close();
return 0;

}

// end of original program

modified program with 2 files (main and header files)

//start of main file (modified program)
#include <fstream>
#include <iostream>
#include "out.h"

using namespace std;

int main (int argc, char * argv) {
ofstream outfile;
outfile.open("out.tmp");

outC my;
my.display(cout);

outfile.close();
return 0;

}

void outC::display (ostream& out) {
out << "testing 1, 2, 3" << endl;

}

// end of main file (modified program)

//start of header file (for the modified program)
#ifndef OUTH
#define OUTH

class outC {
public:
void display (ostream& out);

void display(std:stream& out);

 

[wyndz0108]

#include <ostream>




          void display(std:stream& out);






- Show quoted text -- Hide quoted text -

- Show quoted text -

thank you guys... it's compiling now.

 

[Pete Becker]

the most likely reason it wont compile is that your

using namespace std;

line should be above the
#include "outC.h" header
(or in the outC.h file itself)

Don't mess with namespaces in somebody else's header file. Using
declarations should come after all header includes. Otherwise the
header ends up seeing symbols it may not be prepared for.