Why can't Mata code output?

[qing xuan]

I have a file called hellox.ado that contains the following code:

program hellox
version 15
mata: hello()
end
version 15
mata:
void hello()
{
printf("test output\n")
}
end

Then I use the following code to call it in a do-file:

clear all
do hellox.ado

Why doesn't it output "test output"?

[Nick Cox]

do hellox.ado

defines the program; it does not run it. To see output, run your program with

hellox

Defining the program with a do command is legal but not needed. .ado means automatic do file and that means that do is not needed.

[qing xuan]

I followed your advice, and the code is now running correctly. However, I have a doubt. Thank you very much. Let me express my understanding once again, and please help me correct any mistakes.
In the ado file, the line "mata: hello()" does indeed call the function within the "hellox" command. However, running "do hellox.ado" only defines and loads the "hellox" command into memory, so it doesn't actually execute the "hellox" command. On the other hand, I can directly write the command as follows:

clear all
hellox

[Nick Cox]

That's an accurate rewriting of #2.