(1)用批处理让DOS运算加法减法乘法除法

@echo off
title DOS计算器—by blackboy
mode con: cols=45 lines=20
setlocal enabledelayedexpansion

REM 开始界面
:begin
cls
color 0a
echo.
echo                ╭——————╮
echo        ╭———┤ DOS 计算器 ├———╮
echo        │      ╰——————╯      │
echo        │             =by x2009.cn=  │
echo        │                            │
echo        │          请选择:           │
echo        │                            │
echo        │      1 – 普通＋－×÷      │
echo        │      2 – 求N次方           │
echo        │      3 – 求阶乘            │
echo        │      h – 帮助              │
echo        │      q – 退出              │
echo        │                            │
echo        ╰——————————————╯
REM 取得用户输入
echo.
set UserChoice=”"
set /p UserChoice=请选择:
if /I %UserChoice%==q goto end
if /I %UserChoice%==h goto help
if %UserChoice%==1 goto normal
if %UserChoice%==2 goto fang
if %UserChoice%==3 goto jiecheng
goto error

REM 普通运算
:normal
cls
echo.
echo.
echo.
echo        　　╭—————————╮
echo        　　│ 普通＋－×÷运算 │
echo        　　╰—————————╯
echo.
set /p UserInput=请输入表达式:
REM 检测表达式
echo %UserInput% | findstr “[0-9]“>nul || goto error
echo %UserInput% | findstr /I “[a-z]“>nul && goto error
echo %UserInput% | find “.”>nul && goto error
echo %UserInput% | findstr “+ – * /”>nul || goto error
echo %UserInput% | find “+”>nul && goto add
echo %UserInput% | find “-”>nul && goto minus
echo %UserInput% | find “*”>nul && goto multiply
echo %UserInput% | find “/”>nul && goto divide
REM 实际运算
:add
for /f “tokens=1,2 delims=+” %%a in (“%UserInput%”) do set /a result=%%a+%%b
echo 计算结果=%result%
goto refresh
:minus
for /f “tokens=1,2 delims=-” %%a in (“%UserInput%”) do set /a result=%%a-%%b
echo 计算结果=%result%
goto refresh
:multiply
for /f “tokens=1,2 delims=*” %%a in (“%UserInput%”) do set /a result=%%a*%%b
echo 计算结果=%result%
goto refresh
:devide
for /f “tokens=1,2 delims=/” %%a in (“%UserInput%”) do set /a result=%%a/%%b
echo 计算结果=%result%
goto refresh

REM 计算N次方
:fang
cls
echo.
echo.
echo.
echo        　　╭—————————╮
echo        　　│    求 N 次 方    │
echo        　　╰—————————╯
echo.
set /p UserInput=请输入表达式:
REM 检测表达式
echo %UserInput% | findstr “[0-9]“>nul || goto error
echo %UserInput% | findstr /I “[a-z]“>nul && goto error
echo %UserInput% | find “.”>nul && goto error
echo %UserInput% | find “_”>nul || goto error
set num=
set n=
set /a result=1
for /f “tokens=1,2 delims=_” %%a in (“%UserInput%”) do set /a num=%%a & set /a n=%%b
if %n%==0 goto showfang
for /L %%i in (1,1,%n%) do set /a result*=%num%
:showfang
echo 计算结果=%result%
goto refresh

REM 计算阶乘
:jiecheng
cls
echo.
echo.
echo.
echo        　　╭—————————╮
echo        　　│    求 阶 乘      │
echo        　　╰—————————╯
echo.
set /p UserInput=请输入要求阶乘的整数:
REM 检测表达式
echo %UserInput% | findstr “[0-9]“>nul || goto error
echo %UserInput% | findstr /I “[a-z]“>nul && goto error
echo %UserInput% | find “.”>nul && goto error
set /a result=1
REM 不可以直接判断UserInput是否为0
set num=%UserInput%
if %num%==0 goto showjiecheng
for /L %%i in (%num%,-1,1) do set /a result*=%%i
:showjiecheng
echo 计算结果=%result%
goto refresh

REM 错误
:error
cls
color 0c
echo.
echo.
echo.
echo        ╭————————————╮
echo        │  输入错误,请参考帮助！ │
echo        ╰————————————╯
echo.

REM 刷新
:refresh
echo.
set UserChoice=”"
set /p UserChoice=请按任意键继续,退出请按q,帮助请按h:
if /I %UserChoice%==q goto end
if /I %UserChoice%==h goto help
goto begin

REM 帮助
:help
cls
color 0a
echo.
echo                 ╭——————╮
echo       ╭————┤   帮  助   ├————╮
echo       │        ╰——————╯        │
echo       │                                │
echo       │   1.普通运算请使用以下形式:    │
echo       │       4+1 5-2 2*3 6/2          │
echo       │                                │
echo       │   2.计算N次方请使用以下形式:   │
echo       │        2_5 (求2的5次方)        │
echo       │                                │
echo       │   3.只支持整数运算             │
echo       │                                │
echo       │   4.输入部分特殊符号可能会     │
echo       │     导致意外退出               │
echo       │                                │
echo       ╰————————————————╯
goto refresh

REM 退出
:end
cls
color 0a
echo.
echo.
echo.
echo      ╭————————————————╮
echo      │                                │
echo      │     非常感谢您的使用,　　│
echo      │                                │
echo      ╰————————————————╯
ping -n 2 127.1>nul
exit