【DOS批处理】函数定义和用法
2016-06-16 10:34
204 查看
http://blog.csdn.net/xiaoding133/article/details/39252357
本文主要讲述如下几个问题:
1.什么是函数,怎么创建函数?
2.怎么调用一个函数?
3.函数是怎么工作的?
4.怎么向函数传递参数?
5.函数怎么返回值和返回一个局部变量的值。
一、创建函数(什么是函数)
在batch script 中的函数以一个标签开始,并以goto:eof结束,如下:
script
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plain copy
:myDosFunc - 函数的开始,用一个标签标识
echo. 函数体,可以执行很多命令
echo.
GOTO:EOF
二、调用函数
Script: 01.
call:myDosFunc
三、函数怎么工作
调用函数的脚本将其分成两部分。
1.main script: 从第一行开始并且以 GOTO:EOF命令结束
2.函数部分:由多个函数组成,由main script调用。
SCRIPT:
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@echo off
echo.开始调用函数
call:myDosFunc
echo.从函数返回myDosFunc
echo.&pause&goto:eof
::--------------------------------------------------------
::-- 函数部分开始
::--------------------------------------------------------
:myDosFunc - here starts my function identified by it`s label
echo. here the myDosFunc function is executing a group of commands
echo. it could do a lot of things
goto:eof
三、怎么传递参数,并且在函数中获取参数的值
1.用空格或者逗号将参数分开
2.用双引号将带有空格的字符串参数括起来
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plain copy
call:myDosFunc 100 YeePEE
call:myDosFunc 100 "for me"
call:myDosFunc 100,"for me"
获取参数,采用%1~%9来获取每个参数的值。%0,表示批处理文件本身
[plain] view
plain copy
:myDosFunc - here starts myDosFunc identified by it`s label
echo.
echo. here the myDosFunc function is executing a group of commands
echo. it could do %~1 of things %~2.
goto:eof
带参数的脚本
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plain copy
@echo off
echo.going to execute myDosFunc with different arguments
call:myDosFunc 100 YeePEE
call:myDosFunc 100 "for me"
call:myDosFunc 100,"for me"
call:myDosFunc 100,for me
echo.&pause&goto:eof
::--------------------------------------------------------
::-- Function section starts below here
::--------------------------------------------------------
:myDosFunc - here starts my function identified by it's label
echo.
echo. here the myDosFunc function is executing a group of commands
echo. it could do %~1 of things %~2.
goto:eof
四、函数返回值
1、调用命令不像其他语言那样能有返回值,最常用的做法是在函数中将该值保存在全局变量中,调用结束后
直接用该全局变量。如下:
Usage:
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plain copy
set "var1=some hopefully not important string"
echo.var1 before: %var1%
call:myGetFunc
echo.var1 after : %var1%
Script:
[plain] view
plain copy
:myGetFunc - get a value
set "var1=DosTips"
goto:eof
脚本输出如下:
var1 before: some hopefully not important string
var1 after : DosTips
2、通过引用返回值,调用者通过传递一个变量给函数来存储返回值
Usage:
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call:myGetFunc var1
cho.var1 after : %var1%
Script:
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plain copy
:myGetFunc - passing a variable by reference
set "%~1=DosTips"
goto:eof
脚本输出如下:
var1 after : DosTips
完整脚本:
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plain copy
@echo off
set "var1=CmdTips"
echo.var1 before: %var1%
call:myGetFunc var1
echo.var1 after : %var1%
echo.&pause&goto:eof
::--------------------------------------------------------
::-- Function section starts below here
::--------------------------------------------------------
:myGetFunc - passing a variable by reference
set "%~1=DosTips"
goto:eof
五、函数的局部变量
怎么保证局部变量和全局变量不冲突,SETLOCAL命令能让处理器当做是局部变量,用ENDLOCAL解除局部变量。
ENDLOCAL 会被自动调用,当批处理执行到文件末尾的时候,即GOTO:EOF。SETLOCAL可以很好的保护函数内与外面的变量不会冲突。
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plain copy
@echo off
set "aStr=Expect no changed, even if used in function"
set "var1=No change for this one. Now what?"
echo.aStr before: %aStr%
echo.var1 before: %var1%
call:myGetFunc var1
echo.aStr after : %aStr%
echo.var1 after : %var1%
echo.&pause&goto:eof
::--------------------------------------------------------
::-- Function section starts below here
::--------------------------------------------------------
:myGetFunc - passing a variable by reference
SETLOCAL
set "aStr=DosTips"
set "%~1=%aStr%"
ENDLOCAL
goto:eof
脚本输出:
aStr before: Expect no changed, even if used in function
var1 before: No change for this one. Now what?
aStr after : Expect no changed, even if used in function
var1 after : No change for this one. Now what?
返回局部变量
----怎么跳过ENDLOCAL的屏障,返回局部变量值?
采用”变量扩充“,在SETLOCAL与ENDLOCAL之间的全局变量的值会备份,当退出ENDLOCAL,该值将恢复。让命令处理器来执行ENDLOCAL 和SET命令。
[plain] view
plain copy
@echo off
set "aStr=Expect no changed, even if used in function"
set "var1=Expect changed"
echo.aStr before: %aStr%
echo.var1 before: %var1%
call:myGetFunc var1
echo.aStr after : %aStr%
echo.var1 after : %var1%
echo.&pause&goto:eof
::--------------------------------------------------------
::-- Function section starts below here
::--------------------------------------------------------
:myGetFunc - passing a variable by reference
SETLOCAL
set "aStr=DosTips"
( ENDLOCAL
set "%~1=%aStr%"
)
goto:eof
:myGetFunc2 - passing a variable by reference
SETLOCAL
set "aStr=DosTips"
ENDLOCAL&set "%~1=%aStr%" &rem THIS ALSO WORKS FINE
goto:eof
脚本输出:
aStr before: Expect no changed, even if used in function
var1 before: Expect changed
aStr after : Expect no changed, even if used in function
var1 after : DosTips
六、编写递归函数
让函数局部变量的变换对调用者是可见的,循环调用函数,让变量可重用。下面编写一个函数计算Fibonacci数列。
[plain] view
plain copy
@echo off
set "fst=0"
set "fib=1"
set "limit=1000000000"
call:myFibo fib,%fst%,%limit%
echo.The next Fibonacci number greater or equal %limit% is %fib%.
echo.&pause&goto:eof
::--------------------------------------------------------
::-- Function section starts below here
::--------------------------------------------------------
:myFibo -- calculate recursively the next Fibonacci number greater or equal to a limit
:: -- %~1: return variable reference and current Fibonacci number
:: -- %~2: previous value
:: -- %~3: limit
SETLOCAL
set /a "Number1=%~1"
set /a "Number2=%~2"
set /a "Limit=%~3"
set /a "NumberN=Number1 + Number2"
if /i %NumberN% LSS %Limit% call:myFibo NumberN,%Number1%,%Limit%
(ENDLOCAL
IF "%~1" NEQ "" SET "%~1=%NumberN%"
)
goto:eof
七、总结,定义一个标准的dos batch script function
[plain] view
plain copy
:myFunctionName -- function description here
:: -- %~1: argument description here
SETLOCAL
REM.--function body here
set LocalVar1=...
set LocalVar2=...
(ENDLOCAL & REM -- RETURN VALUES
IF "%~1" NEQ "" SET %~1=%LocalVar1%
IF "%~2" NEQ "" SET %~2=%LocalVar2%
)
GOTO:EOF
本文主要讲述如下几个问题:
1.什么是函数,怎么创建函数?
2.怎么调用一个函数?
3.函数是怎么工作的?
4.怎么向函数传递参数?
5.函数怎么返回值和返回一个局部变量的值。
一、创建函数(什么是函数)
在batch script 中的函数以一个标签开始,并以goto:eof结束,如下:
script
[plain] view
plain copy
:myDosFunc - 函数的开始,用一个标签标识
echo. 函数体,可以执行很多命令
echo.
GOTO:EOF
二、调用函数
Script: 01.
call:myDosFunc
三、函数怎么工作
调用函数的脚本将其分成两部分。
1.main script: 从第一行开始并且以 GOTO:EOF命令结束
2.函数部分:由多个函数组成,由main script调用。
SCRIPT:
[plain] view
plain copy
@echo off
echo.开始调用函数
call:myDosFunc
echo.从函数返回myDosFunc
echo.&pause&goto:eof
::--------------------------------------------------------
::-- 函数部分开始
::--------------------------------------------------------
:myDosFunc - here starts my function identified by it`s label
echo. here the myDosFunc function is executing a group of commands
echo. it could do a lot of things
goto:eof
三、怎么传递参数,并且在函数中获取参数的值
1.用空格或者逗号将参数分开
2.用双引号将带有空格的字符串参数括起来
[plain] view
plain copy
call:myDosFunc 100 YeePEE
call:myDosFunc 100 "for me"
call:myDosFunc 100,"for me"
获取参数,采用%1~%9来获取每个参数的值。%0,表示批处理文件本身
[plain] view
plain copy
:myDosFunc - here starts myDosFunc identified by it`s label
echo.
echo. here the myDosFunc function is executing a group of commands
echo. it could do %~1 of things %~2.
goto:eof
带参数的脚本
[plain] view
plain copy
@echo off
echo.going to execute myDosFunc with different arguments
call:myDosFunc 100 YeePEE
call:myDosFunc 100 "for me"
call:myDosFunc 100,"for me"
call:myDosFunc 100,for me
echo.&pause&goto:eof
::--------------------------------------------------------
::-- Function section starts below here
::--------------------------------------------------------
:myDosFunc - here starts my function identified by it's label
echo.
echo. here the myDosFunc function is executing a group of commands
echo. it could do %~1 of things %~2.
goto:eof
四、函数返回值
1、调用命令不像其他语言那样能有返回值,最常用的做法是在函数中将该值保存在全局变量中,调用结束后
直接用该全局变量。如下:
Usage:
[plain] view
plain copy
set "var1=some hopefully not important string"
echo.var1 before: %var1%
call:myGetFunc
echo.var1 after : %var1%
Script:
[plain] view
plain copy
:myGetFunc - get a value
set "var1=DosTips"
goto:eof
脚本输出如下:
var1 before: some hopefully not important string
var1 after : DosTips
2、通过引用返回值,调用者通过传递一个变量给函数来存储返回值
Usage:
[plain] view
plain copy
call:myGetFunc var1
cho.var1 after : %var1%
Script:
[plain] view
plain copy
:myGetFunc - passing a variable by reference
set "%~1=DosTips"
goto:eof
脚本输出如下:
var1 after : DosTips
完整脚本:
[plain] view
plain copy
@echo off
set "var1=CmdTips"
echo.var1 before: %var1%
call:myGetFunc var1
echo.var1 after : %var1%
echo.&pause&goto:eof
::--------------------------------------------------------
::-- Function section starts below here
::--------------------------------------------------------
:myGetFunc - passing a variable by reference
set "%~1=DosTips"
goto:eof
五、函数的局部变量
怎么保证局部变量和全局变量不冲突,SETLOCAL命令能让处理器当做是局部变量,用ENDLOCAL解除局部变量。
ENDLOCAL 会被自动调用,当批处理执行到文件末尾的时候,即GOTO:EOF。SETLOCAL可以很好的保护函数内与外面的变量不会冲突。
[plain] view
plain copy
@echo off
set "aStr=Expect no changed, even if used in function"
set "var1=No change for this one. Now what?"
echo.aStr before: %aStr%
echo.var1 before: %var1%
call:myGetFunc var1
echo.aStr after : %aStr%
echo.var1 after : %var1%
echo.&pause&goto:eof
::--------------------------------------------------------
::-- Function section starts below here
::--------------------------------------------------------
:myGetFunc - passing a variable by reference
SETLOCAL
set "aStr=DosTips"
set "%~1=%aStr%"
ENDLOCAL
goto:eof
脚本输出:
aStr before: Expect no changed, even if used in function
var1 before: No change for this one. Now what?
aStr after : Expect no changed, even if used in function
var1 after : No change for this one. Now what?
返回局部变量
----怎么跳过ENDLOCAL的屏障,返回局部变量值?
采用”变量扩充“,在SETLOCAL与ENDLOCAL之间的全局变量的值会备份,当退出ENDLOCAL,该值将恢复。让命令处理器来执行ENDLOCAL 和SET命令。
[plain] view
plain copy
@echo off
set "aStr=Expect no changed, even if used in function"
set "var1=Expect changed"
echo.aStr before: %aStr%
echo.var1 before: %var1%
call:myGetFunc var1
echo.aStr after : %aStr%
echo.var1 after : %var1%
echo.&pause&goto:eof
::--------------------------------------------------------
::-- Function section starts below here
::--------------------------------------------------------
:myGetFunc - passing a variable by reference
SETLOCAL
set "aStr=DosTips"
( ENDLOCAL
set "%~1=%aStr%"
)
goto:eof
:myGetFunc2 - passing a variable by reference
SETLOCAL
set "aStr=DosTips"
ENDLOCAL&set "%~1=%aStr%" &rem THIS ALSO WORKS FINE
goto:eof
脚本输出:
aStr before: Expect no changed, even if used in function
var1 before: Expect changed
aStr after : Expect no changed, even if used in function
var1 after : DosTips
六、编写递归函数
让函数局部变量的变换对调用者是可见的,循环调用函数,让变量可重用。下面编写一个函数计算Fibonacci数列。
[plain] view
plain copy
@echo off
set "fst=0"
set "fib=1"
set "limit=1000000000"
call:myFibo fib,%fst%,%limit%
echo.The next Fibonacci number greater or equal %limit% is %fib%.
echo.&pause&goto:eof
::--------------------------------------------------------
::-- Function section starts below here
::--------------------------------------------------------
:myFibo -- calculate recursively the next Fibonacci number greater or equal to a limit
:: -- %~1: return variable reference and current Fibonacci number
:: -- %~2: previous value
:: -- %~3: limit
SETLOCAL
set /a "Number1=%~1"
set /a "Number2=%~2"
set /a "Limit=%~3"
set /a "NumberN=Number1 + Number2"
if /i %NumberN% LSS %Limit% call:myFibo NumberN,%Number1%,%Limit%
(ENDLOCAL
IF "%~1" NEQ "" SET "%~1=%NumberN%"
)
goto:eof
七、总结,定义一个标准的dos batch script function
[plain] view
plain copy
:myFunctionName -- function description here
:: -- %~1: argument description here
SETLOCAL
REM.--function body here
set LocalVar1=...
set LocalVar2=...
(ENDLOCAL & REM -- RETURN VALUES
IF "%~1" NEQ "" SET %~1=%LocalVar1%
IF "%~2" NEQ "" SET %~2=%LocalVar2%
)
GOTO:EOF
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