It probably isn't displaying the string because it crashes before it gets to the code to display the string.

EDIT: {Str1+2I-2} ?  That would make it work with two-byte numbers if you had the ^r.
Just for the record, two hex digits (ie [00]) make one byte, not two.

EDIT2: The code from before you edited it, meaning the code with {Str1+I-1}, works correctly.  What might have happened is it displayed the string and quit so fast you didn't see it?  Try putting a Pause 1900 at the end (pauses for about a second) and then see what happens.

The code from before you edited it, meaning the code with {Str1+I-1}, works correctly.

That meaning, it displayed the string fine, and quit without a cinch.
.ATEST
.[00000000000000000000000000000000]→Str1
Zeros(32)→Str1
.Zeros() does the same thing, but it's easier to code in in this case :P
.worked with initial bunch of 00s as well
"0123456789-+/*^,()"→Str0
For(I,0,15)
{rand^18+Str0}→{Str1+I}
.counting from zero is usually more efficient, in this case the -1 is omitted
End
ClrHome
Disp Str1
Repeat getKey(15)
.wait until clear is pressed
Pause 10
EndWorked without a problem for me.

Is there a way for Axe to input user's numbers? I looked at the command list of axe and there's a 'input' command. Anyone know how to use it?

The reason I edited to {Str1 + 2I - 2} was because each byte in the string with 16 letters represents a letter. So if I=1, position in the string (p) is 0; I=2, p=2, I=3, p=4 and so on. 2I-2 is the order of the 'th' in the string as 'I' increases.

I tried to put Pause 1900 at the end of the code and ran the program, the program paused for a while but still doesn't display anything.

You can't use implicit multiplication in Axe. The correct way to do it is {I*2+Str1-2}.

Input is really buggy, personally I'd only use it as a last resort.  You'd probably be better off making your own input routine (or use one from the routines thread, such as this from the routines thread)

Yes, that's the only way to do it, even though I never managed to do it, even with the routines. I wish somebody posted an example

Your first two questions are the answers to each other. The "While B-9→B>9:End"  limits the number to 0-9. The "ReturnIf A not equal to 0" causes the program to go back to after the subroutine is called. I think you can use the Output( command in a way similar to basic, the command list will probably say.

I have no idea, this comes with the axe 0.5.3 package