# P33 - Determine whether two positive integer numbers are coprime.

Author: Philip Potter

# Specification

```P33 (*) Determine whether two positive integer numbers are coprime.
Two numbers are coprime if their greatest common divisor equals 1.```

# Example

```> say coprime(35,64)
1```

Source code: P33-rhebus.pl

```use v6;

# This is from P32-rhebus.pl
sub gcds (Int \$a, Int \$b) {
return (\$a, \$b, *%* ... 0)[*-2];
}

sub coprime (Int \$a, Int \$b) { gcds(\$a,\$b) == 1 }

say coprime(35,64);

# Another option is to make coprime an operator:
# (theoretically 'our' is unnecessary but rakudo needs it
our sub infix:<coprime> (Int \$a, Int \$b) { gcds(\$a,\$b) == 1 }

# All adjacent fibonacci pairs are coprime.
# We can test a number of fibonacci pairs at once
# with the hyper operator »coprime«

my @fib = (1,2,3,5,8,13,21,34,55);
say \$_ for @fib[0..^+@fib-1] »coprime« @fib[1..^+@fib];

# And here's another famous series:
my @pow = (1,2,4,{\$_*2} ... 4096);
say \$_ for @pow[0..^+@pow-1] »coprime« @pow[1..^+@pow];

```