Can't Compile a Simple Program

I am new to C++ and am tryind to compile a simple program under Linux. The code is in the form of:

#include <stdio.h>
int main()
{
cout << "Hell World";
return 0;
}



When trying to compile, I get the error messages as follows:

test.cpp: In function 'int main()':
test.cpp: 'cout' undeclared (first use this function)
text.cpp: (Each undeclared identifier is reported only once for each function it appears in.)



What have I done incorrectly ?

Pete

Try this instead

Code:

---

#include <iostream>
using namespace std;
 
int main()
{
  cout << "Hell World";
  return 0;
}

---

Or if you have a cheap compiler that doesn't like namespaces, replace the first two lines with #include <iostream.h>

stdio.h contains the i/o functions for C, C++ uses iostream instead.

-Prelude

G'Day Prelube,

So what does 'namespace' actually do ??

Pete

If you are just begining, it is too complicated to explain to you. But I'll try anyways.

If you want to use different things with the same name, you can put them in different namespaces to avoid the conflict. That whole using line tells the compiler that u r using the std (standard) namespace.

I'd like to know what namespaces are too. I've noticed you don't put in the .h in the include files. Go ahead, use technical terms.

Hell World :)

G'Day SilentStrike,

Yea...... sometimes I wonder :-)

But is really ment to be "Hello"

Pete

I managed to get it going but instead of using:

cout << "Hello World";

I had to use:

puts("Hello World");

before it would compile - why is this so ?

Pete

Did you try Prelude's code? If that didn't work, perhaps you have only a C compiler rather than a C++. Tell us a bit more about your environment.

G'Day Adrian,

Yea, you could be right there - yes I did try the code but kept on getting the same results until I used 'puts'.

I am using Linux (Mandrake 8.1) and the compiler I'm using is "gcc".

Pete

I don't use either I'm afraid, but have a browse at the link below. It says it will compile C++ amongst other things. You might need to set some option or other to make it compile C++.

http://gcc.gnu.org/

Does your source file have a .c or a .cpp extension? If .c, you might try changing it to .cpp.

*** EDIT ***

Try using g++ rather than gcc!!!

http://www.cprogramming.com/cboard/s...threadid=10470

let's say you have a project that has two different user defined header files. In each header file is a fucntion called loadData(). Both copies of loadData() have the same return type, and the same parameters, but the function bodies differ. When you call loadData() in main() how is the compiler going to know which version you intend to use, as the prototypes are the same, even if the body of the functions aren't?. Well, one way might to make the two prototypes of loadData() different somehow. Or you could take loadData() out of the two headers, modify it to cover both function bodies, and place it in a third header file, or make it global,or whatever. Last, but not least, would be to create a new level of organization, called namespace, such that when you want to use the version from namespace A you so indicate and when you want to use the version from namespace B you so indicate. I don't know all the details of declaring namespaces, and I can't find it readily in my online reference, but I think you use them something like this:

namespace std;//all the routine I/O handling is in here
namespace A;//user created namespace, holds headers, etc.
namespace B;//user created namespace, holds headers, etc.

std::cout << "What's up doc?" << std::endl;
A::loadData();
B::loadData();

I think that gives you the idea, but the details we both need to look up.

i am new to C++ to but i would try somthin like\

#include <iostream.h>
void main( void )
{

cout << "Hell World ";
return 0;
}

The reason the original code didnt work is because he was useing cout with stdio.h you need to use iosream.h for cout and stdio.h for printf and scanf and such

yeah... I'm new too... am I able to do the following:

#include <stdio.h>
#include <iostream.h>
int main()
{
cout << "Hell World";
return 0;
}

I think u can... anyone?

Yes

Get a good code editor setup a template type thingy that looks like this

#include <iostream.h>
#include <stdio.h>
/* Any other headers */

int main(int argc, char* argv[])
{
/* code */
return 0;
}

so when the editor loads up it puts that there at the same time...and yes you can have all the headers you want and yes cout is in iostream and puts printf and all those ones are in stdio so its easier to put both just in case...

Use <iostream.h> instead of <stdio.h>. Iostream is used to print text, stdio is not.

The program should look like this:

Code:

---

#include <iostream.h>
int main()
{
cout << "Hello World";
return 0;
}

---