Compiling and running Fortran programs

Before your program can be executed, it must be compiled. Compiling the program works by converting the English-like text of a Fortran program into a binary form that the processor understands.

You compile a program by typing a line similar to the following:

	f77 -o myprogram myprogram.f

It is important that you understand what is happening here:

• f77 is the name of the Fortran compiler. Computers that run the Unix operating system often use the name for the Fortran compiler, though your compiler may have a different name such as g77 or pgf77.
• The -o option tells the compiler that the next word (here, myprogram) will be the name of the binary version of the program. If you omit this option, most systems will automatically name the binary version a.out regardless of the name of your program. It's perfectly legal to use this default, though it's usually helpful to use a more meaningful name. The binary file is often called the executable file because the computer can run (execute) it.
• myprogram.f is the name of the file that contains the source code of your program. The source code is the file of instructions that you actually edit and type. Your source file could be named something other than myprogram.f, such as homework1.f. or some other descriptive name. On many systems the name of the source file must end with the suffix .f or the compiler is apt to become unhappy.

To run the program, simply type the name of the executable file:

	myprogram