中国DOS联盟

@echo off&setlocal EnableDelayedExpansion
set num1=0
set num2=0

for /f "delims= " %%i in (a.txt) do (
    set var=%%i
    if defined var goto begin
)

:begin
for /f "skip=1 delims= " %%i in (a.txt) do (
    set bar=!var!
    set var=%%i
    set /a car=!var!-!bar!
    echo !car!>>b.txt
)
set /a car=!bar!-!bar!
echo !car!>>b.txt
goto insert

:insert
for /f "tokens=1,2 delims= " %%a in (a.txt) do (
    set /a num1+=1
    for /f "delims=" %%i in (b.txt) do (
        set /a num2+=1
        if !num1!==!num2! echo %%a %%i %%b>>c.txt
    )
    set num2=0
)
del b.txt
endlocal
goto :eof

@echo off
Setlocal Enabledelayedexpansion
type nul>b.txt
set /a m=0,n=m-1
for /f "tokens=1,*" %%a in ('type a.txt') do (
  set str!m!=%%a&set var!m!=%%b
  if !m! gtr 0 (
    set /a sth=str!m!-str!n!
    >>b.txt call echo %%str!n!%% !sth! %%var!n!%%
  )
  set /a m+=1,n+=1
)