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DOS批处理 & 脚本技术（批处理室） » Set out a question, all picked from C language questions by me

Floor16　slore	Posted 2008-04-11 21:10
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Narc narcissistic number It is suggested to use three nested loops...

Floor17　bat-zw	Posted 2008-04-11 21:42
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Because cmd is limited to 10-digit numbers, using this method can only accurately calculate the height of the ball bouncing up on the 10th landing, and the distance traveled in 10 passes cannot be accurately calculated (depressed): @echo off set /a n=10010000000&set m=0 :begin if %m% gtr 0 set str=%str%+2%n% if %m% gtr 0 set /a str=%str%/10000000 set /a n/=2&set /a m+=1 if %m% lss 10 goto begin set /a str=%str%+100/2 echo The total distance after the 10th landing of the ball is %str% meters :lp if "%n:~,-6%"=="" set n=0%n% if "%n:~,-6%"=="" goto lp echo The 10th bounce is 0.%n% meters pause>nul [ Last edited by zw19750516 on 2008-4-11 at 10:05 PM ]

Floor18　bat-zw	Posted 2008-04-11 22:26
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```@echo off&setlocal enabledelayedexpansion set n=10 for %%i in (2,2,2,2) do set /a n+=%%i&cls&echo The fifth person is!n! years old pause>nul ```

Floor19　terse	Posted 2008-04-11 22:34
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The Narcissistic number algorithm is indeed better with three nested loops. The following one was forgotten who the moderator wrote, but I remember it was written by moderator namejm: @echo off echo. echo Three-digit narcissistic numbers are: echo. setlocal enabledelayedexpansion for /l %%i in (1,1,9) do ( for /l %%j in (0,1,9) do ( for /l %%k in (0,1,9) do ( set a=%%i set b=%%j set c=%%k set num1=!a!!b!!c! set /a num2=!a!!a!!a!+!b!!b!!b!+!c!!c!!c! if !num1! equ !num2! echo !num1! ) ) ) pause goto :eof

Floor20　bat-zw	Posted 2008-04-11 22:35
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@echo off set /a str=6777774 echo There can be %str% odd numbers formed pause>nul

Floor21　bat-zw	Posted 2008-04-11 22:41
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Originally posted by terse at 2008-4-11 22:34: The narcissistic number algorithm is indeed better with three nested loops. The following one I forgot who the moderator wrote, I remember it was written by moderator namejm: @echo off echo. echo Three-digit narcissistic numbers are: echo. setlocal ... I don't think so. My code can implement it very well (I initially missed a *), why write such complicated code.

Floor22　slore	Posted 2008-04-11 23:47
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In terms of efficiency, a 3-layer loop is better than looping from 111 to 999. For program code, efficiency is the top priority.

Floor23　terse	Posted 2008-04-11 23:54
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If it's simple, then directly SET/a var var=!str:~,1!!str:~,1!!str:~,1!+!str:~1,1!!str:~1,1!*!str:~1,1!.....

Floor24　26933062	Posted 2008-04-12 00:16
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Personally, there is no difference in efficiency between floor 15 and floor 19. However, it is unnecessary for floor 15 to put the delay variable inside the for. If you want to prove which one has higher efficiency, it is best to rely on facts. To find the narcissistic numbers from 1 to 10000 and record the batch processing running time, isn't that a result?

Floor25　plp626	Posted 2008-04-12 00:43
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The so-called "narcissistic number" refers to a three-digit number whose sum of the cubes of its digits is equal to the number itself. 15th floor: @echo off setlocal enabledelayedexpansion for /l %%i in (100,1,999) do ( set str=%%i set/a a=!str:~,1!, b=!str:~1,1!, c=!str:~2,1! set /a var=!a!!a!!a!+!b!!b!!b!+!c!!c!!c! if !var! equ !str! echo !str! ) pause 19th floor: @echo off setlocal enabledelayedexpansion for /l %%i in (1,1,9) do for /l %%j in (0,1,9) do for /l %%k in (0,1,9) do ( set/a a=%%i,b=%%j,c=%%k set num1=!a!!b!!c! set /a num2=!a!!a!!a!+!b!!b!!b!+!c!!c!!c! if !num1! equ !num2! echo !num1! ) pause [ Last edited by plp626 on 2008-4-12 at 12:51 AM ]

Floor27　slore	Posted 2008-04-12 14:45
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Are the number of loops the same? Which one is less? Which is faster, taking each digit or combining several digits?

Floor28　26933062	Posted 2008-04-12 15:00
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Originally posted by slore at 2008-4-12 14:45: Are the number of loops the same? Which one is less? Which is faster, taking each digit or combining several digits? To find the Armstrong numbers from 1 to 10000 and record the batch processing time, wouldn't that give the result?

Floor29　plp626	Posted 2008-04-12 16:09
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Originally posted by 26933062 at 2008-4-12 03:00 PM: Find the narcissistic numbers from 1 to 10000, and record the batch processing running time, then you will get the result? The two times are the same, with an error within 0.01 seconds, which is less than the "system" error of %time%.

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