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Question

How to write a factorial function recursivly ?

Answer

A recursive function is a function that repeatedly calls itself.
No limit is placed on the number of recursive calls.
Create a shell script called fact.sh:

 #!/bin/bash
# fact.sh - Shell script to to find factorial of given command line arg
factorial () {
 local i = $1
 local f
 declare -i i
 declare -i f

 # factorial() is called until the value of $f is returned and is it is <= 2
 # This is called the recursion
 [ $i -le 2 ] && echo $i || { f = $(( i - 1 ))
 f = $( factorial $f )
 f = $(( f * i ))
 echo $f ; } }

# display usage [ $# -eq 0 ] && { echo "Usage: $0 number" ; exit 1 ; }
# call factorial
factorial $1

Save and close the file. Run it as follows:

 chmod +x fact.sh
./fact.sh
./fact.sh 2 ./fact.sh 5

Question

How to write a factorial function recursivly ?

Answer

Question

How to write a factorial function recursivly ?

Answer

A recursive function is a function that repeatedly calls itself.
No limit is placed on the number of recursive calls.
Create a shell script called fact.sh:

 #!/bin/bash
# fact.sh - Shell script to to find factorial of given command line arg
factorial () {
 local i = $1
 local f
 declare -i i
 declare -i f

 # factorial() is called until the value of $f is returned and is it is <= 2
 # This is called the recursion
 [ $i -le 2 ] && echo $i || { f = $(( i - 1 ))
 f = $( factorial $f )
 f = $(( f * i ))
 echo $f ; } }

# display usage [ $# -eq 0 ] && { echo "Usage: $0 number" ; exit 1 ; }
# call factorial
factorial $1

Save and close the file. Run it as follows:

 chmod +x fact.sh
./fact.sh
./fact.sh 2 ./fact.sh 5

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Recursive function - Linux Shell Scripting Tutorial - A Beginner's handbook
- A Beginner's handbook Recursive function From Linux Shell Scripting Tutorial - A Beginner's handbook Jump to navigation Jump to search ← Source command Home Putting functions in background → <span>A recursive function is a function that repeatedly calls itself. No limit is placed on the number of recursive calls. Create a shell script called fact.sh: #!/bin/bash # fact.sh - Shell script to to find factorial of given command line arg factorial(){ local i=$1 local f declare -i i declare -i f # factorial() is called until the value of $f is returned and is it is <= 2 # This is called the recursion [ $i -le 2 ] && echo $i || { f=$(( i - 1)); f=$(factorial $f); f=$(( f * i )); echo $f; } } # display usage [ $# -eq 0 ] && { echo "Usage: $0 number"; exit 1; } # call factorial factorial $1 Save and close the file. Run it as follows: chmod +x fact.sh ./fact.sh ./fact.sh 2 ./fact.sh 5 Sample outputs: 2 120 You can debug the script as follows: bash -x ./fact.sh 5 Sample outputs: + '[' 1 -eq 0 ']' + factorial 5 + local i=5 + local f + declare -i i + declare -i f + [[ 5

Summary

status	not learned	measured difficulty	37% [default]	last interval [days]
repetition number in this series	0	memorised on		scheduled repetition
scheduled repetition interval		last repetition or drill

Details

No repetitions

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