如何在批处理文件中进行数学运算 [英] How to do math in batch-file

问题描述

我一直在想可以使用的批处理代码遇到麻烦，但是不要...

I have been having troubles with batch-codes that I would expect to work, but don't...

下面是我写的...

@echo off
cls

:loop
set /p "input=Input a number: "
set /a "number=%input%" 2>nul
REM check if input valid
if "%input%" NEQ "%number%" (
cls
Echo Please Enter a valid number! &Echo.&Echo.
goto :loop
)
Set /a Even=number%%2
if %Even% EQU 0 (
Echo Substituting Even Number in: x / 2
Echo set /p"=(%number%) / 2 = "
set /a answer=number/2
) Else (
Echo Substituting Odd Number in: 3x - 1
<nul set /p"=3(%number%)-1 = "
set /a answer=number*3
set /a answer=answer-1
)
Echo %answer%
Echo.
Echo.

goto :loop
Echo Unexpected Error . . .
pause
Exit

每当我在控制台中输入数字时，它都会像我希望的那样进行数学运算，但是会打印数字-1，并且每次我输入另一个数字时，数字都会变为-2，-3，-4 ，等等.

Whenever I input a number into the console, it does the math, like I want it to, but prints the number -1, and every time i input another number, the number goes to -2, -3, -4, so on.

推荐答案

在@echo off之后的开头放置一个setlocal enableextensions，例如

Put a setlocal enableextensions at the beginning after the @echo off, e.g.

@echo off
setlocal enableextensions
cls

此外，我认为您还需要使用延迟的变量扩展(通常用!var!表示)，这会将上面的脚本更改为类似以下内容:

Also, I think you would also need to use delayed variable expansion (usually denoted by !var!), which would change your script above to something like this:

@echo off
setlocal enableextensions enabledelayedexpansion
cls

:loop
set /p "input=Input a number: "
set /a number=!input! 2>nul
REM check if input valid
if "!input!" NEQ "!number!" (
cls
Echo Please Enter a valid number!
Echo.
Echo.
goto :loop
)
REM Make sure that it is an integer put in (just in case)
set /a int=!number! %% 1
if "!input!" NEQ "!int!" (
cls
Echo Please Enter a valid number!
Echo.
Echo.
goto :loop
)
Set /a Even=!number! %% 2
if !Even! EQU 0 (
Echo Substituting Even Number in: x / 2
set /a answer=!number! / 2
) Else (
Echo Substituting Odd Number in: 3x - 1
set /a answer=!number! * 3 - 1
)
Echo !answer!
Echo.
Echo.

goto :loop

我还想指出的是，我还修复了一些其他错误(set /p在此脚本中根本没有任何用处，尤其是在使用该脚本的地方，而且您还需要模数才能找到甚至/odd).

I also would like to point out that I also fixed a few other bugs (set /p isn't of any use in this script at all, especially in where it is used, and also you need the modulus to find even/odd).

这篇关于如何在批处理文件中进行数学运算的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！