中国DOS联盟

@echo off
echo a=b+c
:hom
set/p a="a="
set/p b="b="
set/p c="c="

if %a%==? set/p a="a="<nul &set/a ?=%b%+%c%
if %b%==? set/p b="b="<nul &set/a ?=%a%-%c%
if %c%==? set/p c="c="<nul &set/a ?=%a%-%b%

echo %?%
goto hom


一共就这么多,各位给看一下哈!!!!

SET /A expression
SET /P variable=[promptString]

The /A switch specifies that the string to the right of the equal sign
is a numerical expression that is evaluated.

The /P switch allows you to set the value of a variable to a line of input
entered by the user. Displays the specified promptString before reading
the line of input. The promptString can be empty.