中国DOS联盟

Narc narcissistic number

It is suggested to use three nested loops...

@echo off

set /a n=100*10000000&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 第10次球落地后共经过%str%米的距离

:lp

if "%n:~,-6%"=="" set n=0%n%

if "%n:~,-6%"=="" goto lp

echo 第10次弹起为0.%n%米

pause>nul

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=100*10000000&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 ]

@echo off&setlocal enabledelayedexpansion

set n=10

for %%i in (2,2,2,2) do set /a n+=%%i&cls&echo 第五个人年纪是!n!岁

pause>nul

```@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
```

@echo off

echo.

echo         三位的水仙花数有：

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

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

@echo off

set /a str=6*7*7*7*7*7*4

echo 能组成%str%个奇数

pause>nul

@echo off

set /a str=6*7*7*7*7*7*4

echo There can be %str% odd numbers formed

pause>nul

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.

In terms of efficiency, a 3-layer loop is better than looping from 111 to 999.

For program code, efficiency is the top priority.

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!.....

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?

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 ]

Are the number of loops the same?
Which one is less?
Which is faster, taking each digit or combining several digits?

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?

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%.

If you can test up to 99999999999999999999999999999999999...