2

I have solved Project Euler Problem 3, but the thing is that I am not able to create the function in awk.

I have tried this working code (without function):

#!/usr/bin/awk -f
BEGIN{
    n=600851475143;
    x=2; # minimal prime
    while ( x<n ) {
        if ( (n%x) == 0 ) {
            n = n/x
            print n
        } else { # if n not divisible then increment x+1
            x++
        }
    }
}

Not working with the function

#!/usr/bin/awk -f
# The prime factors of 13195 are 5, 7, 13 and 29.
# What is the largest prime factor of the number 600851475143 ?

function get.PrimeFactor(n) {
    x=2; # minimal prime
    while ( x<n ) {
        if ( (n%x) == 0 ) {
            n = n/x
            print n
        }
        else { # if n not divisible then increment x+1
            x++
        }
    }

BEGIN {
    n = $1 # input number by user
    get.PrimeFactor(n)
}

I have tried several ways to work with the function but no luck.

Can anyone highlight what I'm doing wrong?

Improve this question

2 Answers 2

Reset to default
2

Get rid of the dot. Valid awk function names consist of a sequence of letters, digits and underscore, and don't begin with digit.

Improve this answer
7
  • hmm.. good to know... let me check with that.. thanks.. Commented May 9, 2013 at 6:30
  • now it is working.. but another issue why it not accepting $1 input value as command argument Commented May 9, 2013 at 6:43
  • I'm trying awk -f script value and it is not taking value as $1 Commented May 9, 2013 at 6:43
  • To get shell variables into awk you need to do something like this: **awk -vinput=$1 '{ print input }' ** Commented May 9, 2013 at 6:50
  • 1
    @tink, you forgot quotes around $1 and beware that with that syntax, awk expands ANSI C escape sequences (\n, \b...) in the argument provided. Using ENVIRON or ARGV doesn't have that problem. Commented May 9, 2013 at 10:28
0

Working AWK Script with function.

#!/usr/bin/awk -f
# The prime factors of 13195 are 5, 7, 13 and 29.
# What is the largest prime factor of the number 600851475143 ?

function get_PrimeFactor(n) {
    x=2; # minimal prime
    while ( x<n ) {
        if ( (n%x) == 0 ) {
            n = n/x
        }
        else { # if n not divisible then increment x+1
            x++
        }
    }
    return n
}

BEGIN {
    n = ARGV[1] # input number by user
    print get_PrimeFactor(n)
}
Improve this answer

You must log in to answer this question.

Start asking to get answers

Find the answer to your question by asking.

Ask question

Explore related questions

See similar questions with these tags.