I recommend to first open a command prompt, run set /?
and read the output help carefully and completely from top of first to bottom of last page. There is explained:
Any non-numeric strings in the expression are treated as environment variable names whose values are converted to numbers before using them. If an environment variable name is specified but is not defined in the current environment, then a value of zero is used. This allows you to do arithmetic with environment variable values without having to type all those % signs to get their values.
So there can be written just set /A npchp=npclvl * 100
as npclvl
inside the arithmetic expression is interpreted as name of an environment variable and the command line works even on being inside a command block starting with (
and ending with matching )
without usage of delayed environment variable expansion.
Then run cmd /?
and read again the output help carefully and completely from top of first to bottom of last page. There is explained that a file name (or any other argument string) containing a space one of these characters &()[]{}^=;!'+,`~
must be enclosed in "
to get those characters interpreted as literal characters of an argument string.
Please read also How does the Windows Command Interpreter (CMD.EXE) parse scripts?
For that reason the command line set /a npcdef=(%npchp%*5)/100
should be written with one of the following notations:
set /A npcdef=npchp*5/100
set /A npcdef=npchp * 5 / 100
set /A "npcdef=(npchp*5)/100"
set /A npcdef=(npchp*5^)/100
The caret character ^
escapes the next character for being interpreted as literal character except the next character is %
which must be escaped with %
.
The recommendations posted on DosTips forum topic ECHO. FAILS to give text or blank line - Instead use ECHO/ should be also taken into account on writing batch files which output empty lines.
The batch file with the main improvement of changing the IF condition to avoid completely the usage of a command block.
@echo off
setlocal EnableExtensions DisableDelayedExpansion
%SystemRoot%\System32\mode.com con cols=110 lines=32
set npctier=0
set "npctype=Wooden Dummy"
:randomnpc
if %npctier% NEQ 0 goto CombatChoice
set /A npclvl=%random% %% 5 + 1
set /A npchp=npclvl*100
set npcdmg=0
set /A npcdef=npchp*5/100
set /A npcxp=npclvl*100
:CombatChoice
echo(
echo You see %npctype% level %npclvl%.
echo(
echo The %npctype%'s health: %npchp% HP
echo(
endlocal
See also Why is no string output with 'echo %var%' after using 'set var = text' on command line? It contains several hints on how to use command SET not written in help/documentation of this command.