Hello world: simple console output¶
A good feature to learn first in any language is how to print things out to the console. Although Chapel has a sophisticated set of I/O features, let’s just focus on a simple capability to get started.
The writeln() procedure prints its list of comma-separated
arguments to the console, one after the other without spaces, followed
by a newline. Thus, the following statement will print a greeting to
the console:
writeln("Hello Chapel Users!");
This guide will cover the Chapel program structure in more detail later;
for now, it’s sufficient to know that a Chapel program can simply be a
sequence of statements in a file. Thus, the statement above is a
complete Chapel program. If you type or paste it into a text editor
and save it into a file, say hello.chpl, you’ll have written your
first Chapel program.
Given a working Chapel compiler (see Downloading Chapel for details), you can compile the program using:
chpl hello.chpl -o hello
which says to compile the hello.chpl Chapel source file, naming
the output binary hello. Once the compiler is done, you can run
the program using:
./hello
The program should then print the greeting to your console as follows:
Hello Chapel Users!
And with that, you’ve executed your first Chapel program!