View source for Compiling C++ programs with EMX the Easy Way

''By [[Greggory D. Shaw]]''

==Introduction - Beginners Level==
After I finished my college programming requirements using Java I decided to try [[C++]] and of course I wanted to use Warp as my programming platform. Well, trying to find a starting place, I checked out the Devcorner on NetLabs. I needed a compiler. The section on compilers included information about C/C++, Pascal, and Java. I ended up picking EMX GCC for OS/2, it's the port of the GNU C/C++ compiler.

Well after many hours of downloading files, reading through the documentation and editing my CONFIG.SYS file too many times. I finally got to compile my first three line C++ program.

Just to compile this simple program, it took about 7 files and 23 optional files to use the GNU C/C++ compiler with EMX. I could have been missing something, but even if I got everything set up perfectly the first time, the installation and set up should easier. So this is why I am writing this article to show you how to get a quick and easy programming environment. So if you decide to throw your C++ book out the window half way through the second chapter, you are not out hours of work.

==How to get EMX==
The easy way is with one click and that's it. The EMX 0.9d Development Package in WarpIN format is on {{FileLink|EMX_0-9-d.wpi}}. The source is unknown and I do not know how complete it is, but it works for what we need it to do. Plus it can be easily uninstalled by WarpIN.

==How to Install EMX==
The following describes installing EMX and adding additional lines to your CONFIG.SYS that the WarpIN package fails to do. Some of the extra lines enable you to compile C++ programs.

Start the installation.
# The Readme.doc is displayed. Click next.
# The GNU General Public License is displayed. Click next to agree to it.
# Select the packages to install. I selected everything but the sources (23MB). Click next.
# Modify CONFIG.SYS Dialog is displayed. Click next.
# Installation dialog. Click next, select YES to install all packages.
# Add these lines to the CONFIG.SYS.
#:<tt>SET CPLUS_INCLUDE_PATH=c:/emx/include/cpp;c:/emx/include
#:SET PROTODIR=c:/emx/include/cpp/gen
#:SET OBJC_INCLUDE_PATH=c:/emx/include
#:SET TERM=ansi
#:SET TERMCAP=c:/emx/etc/termcap.dat</tt>
# Reboot and you are Ready to Compile!

==Using the Compiler==
Time to start writing a C++ program, that we can compile. I fired up the [[System Editor]].
<code>
 // convert.cpp
 // this programs converts between Celsius & Fahrenheit
 include <iostream>
 int main()
 {
 int ftemp;
 int ctemp;
 int select = 0;
 //***** Prints instr. & inputs your selection *******************
 cout << "Select conversion: " << endl;
 cout << "1) Fahrenheit to Celsius" << endl;
 cout << "2) Celsius to Fahrenheit" << endl << endl;
 cout << "Enter: ";
 cin >> select;  // input your selection
 //***** Converts F to Celsius *********************************
 if (select == 1)
 {
 cout << "\nEnter temperature in Fahrenheit: ";
 cin >> ftemp;
 ctemp = (ftemp-32) * 5 / 9;
 cout << "Equivalent in Celsius is: " << ctemp << endl;
 } //End of IF
 //****** Converts C to Fahrenheit ****************************
 else if (select == 2)
 {
 cout << "\nEnter temperature in Celsius: ";
 cin >> ctemp;
 ftemp = ctemp*9/5 + 32;
 cout << "Equivalent in Fahrenheit is: " << ftemp << endl;
 } //End of IF
 //***** Prints message if invalid choice is made ***********
 else
 cout << "Valid options 1 or 2." << endl;
 return 0;
 } // End of Main
</code>
Okay short and simple, but it will compile. Now you can save it to any directory. I save my files to c:\cp to keep all my programs together. Open up an OS/2 command line window and type: "cd cp" to change directories. Now it's time to compile convert.cpp. To do this type:
 gcc convert.cpp -lstdcpp -s
That's it! Now we can run the program.
 convert
And this is displayed on the screen.
 Select conversion:
 1) Fahrenheit to Celsius
 2) Celsius to Fahrenheit
 Enter:

==More Information==
The next place to go after this, is the article [http://www.os2ezine.com/20020716/page_7.html EMX on the Desktop] by James Cannon featured in the July issue of the OS/2 eZine. And the original article [http://www.edm2.com/0101/emx.html Installing EMX] by Brooke P. Anderson. There are many C++ tutorials on the Internet, the [http://www.cplusplus.com/doc/tutorial/ cplusplus.com tutorial] is one, and there is a link at the bottom of the page on compiling console programs with different compilers (Windows, Linux, UNIX). The book ''Object-Oriented Programming in C++'', 3rd Ed. by [[Robert Lafore]] is what I am using. Every program that I tried though the sixth chapter compiled without problems, minus two that used a graphics library.

==Conclusion==
I hope that this will save you some time on setting up your C++ programming environment so you can jump right into programming. And try at least to get through the third chapter of your C++ book, because the first two chapters put me to sleep.

Thanks to Brooke P. Anderson and James Cannon for the inspiration for this article.

[[Category:C++ Articles]]