You have 2 problems:
1) You are confusing FOR variables with environment variables. A batch FOR variable name is always a single character, and it is access via 2 percents prior to the name:
%%c. A FOR variable value cannot be changed with SET.
An environment variable name can contain multiple characters, though it can be a single character, and it is accessed by enclosing the name in percents:
%var%. Exclamation points can be used if you want delayed expansion:
!var!. An environment variable value is set with SET.
2) The CALL trick to access environment variable values that were set within a parenthesized code block is used at expansion time, not when you are setting the value.
I believe mousio provided provided the best answer; I always use delayed expansion like in that answer. But it is possible to do what you want without delayed expansion by properly using an environment variable and the CALL trick.
for /f "tokens=1-3 delims=," %%a in (Puck.csv) do (
echo Hello No Hockey>%%a.txt
echo #:A %%a>>%%a.txt
echo #:B %%b>>%%a.txt
if /i %%c gtr 10 set C=1
call echo #:C %%C%%>>%%a.txt
Note that it is critical that the case of the FOR variable is different than the environment variable. FOR variables are case sensitive, environment variables are not. If you use
c for both, then the parser will treat
%%c%% as the FOR variable followed by a percent - not what you want.