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StartingCPP

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Starting with C++

g++ (GNU C++ compiler)

First of all, you need g++, which is most likely already installed if you use Gentoo. It's best to make sure, though:

Code: Checking g++ version
g++ --version

At my box here it returns:

Code: Output
 g++ (GCC) 3.3.5  (Gentoo Linux 3.3.5-r1, ssp-3.3.2-3, pie-8.7.7.1)

Hello World!

Right, on to the real thing! Fire up your editor and insert this into a new file:

File: helloWorld.cpp
#include <iostream>

int main () 
{
       std::cout << "Hello world in ANSI-C++\n";
       return 0;
}

Save the file as helloWorld.cpp. Now we have to compile it to a binary file, so we can run it. Run the following commands:

Code: Compile and run your program.
 $ g++ helloWorld.cpp
 $ ./a.out

The latter executes your freshly compiled program.

Make Life Better

All right, a couple of things can be done better. First of all, let's make some changes to the source code:

File: A better helloWorld.cpp
#include <iostream>

using namespace std;

int main () 
{
       cout << "Hello world in ANSI-C++\n";
       return 0;
}

Now we won't have to type std:: each time.


A file named a.out isn't very nice either, instead of running

Code:
g++ helloWorld.cpp

We should run:

Code:
g++ helloWorld.cpp -o hello

The generated file will then be called hello instead of a.out.

Note that the compiler will write "return 0" for you, but only for the main function.

Summary

  1. Create a .cpp file
  2. Compile it: g++ helloWorld.cpp -o hello
  3. Alternatively compile it for Windows using i386-mingw32msvc-g++ ./helloWorld.cpp -o hello.exe
  4. Run it! ./hello

That's pretty easy, huh? Buy a fun book about C++ and learn the language!

Wesley

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Last modified: Mon, 13 Oct 2008 03:33:00 +0000 Hits: 18,083