Re^3: decimal to binary conversion

The usage for <=> here in the masking expreasion ($decimal & 0x80) is to test if this 8th bit is zero or one, also you can do it like:

#!/usr/bin/perl -w 
use strict; 
use warnings; 

print "Enter decimal number less than 256:"; 
my $decimal; 
$decimal=<STDIN>; 
chomp $decimal; 
# $decimal += 0;
print (($decimal & 0x80)? (1) : (0) );    # to test the 8th bit
print (($decimal & 0x40)? (1) : (0) );    # to test the 7th bit
print (($decimal & 0x20)? (1) : (0) );    # to test the 6th bit
print (($decimal & 0x10)? (1) : (0) );    # to test the 5th bit
print (($decimal & 0x08)? (1) : (0) );    # to test the 4th bit
print (($decimal & 0x04)? (1) : (0) );    # to test the 3th bit
print (($decimal & 0x02)? (1) : (0) );    # to test the 2nd bit
print (($decimal & 0x01)? (1) : (0) );    # to test the 1st bit
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Re^4: decimal to binary conversion by AnomalousMonk (Archbishop) on Jun 05, 2015 at 15:24 UTC
Are so many parentheses needed with the lower precedence `? :` Conditional Operator? Also, rather than using what looks like an unrolled loop for printing bits, is there any way to use a `while`- or `for`-loop here? Give a man a fish: `<%-(-(-(-<`	[reply] [d/l] [select]
Re^5: decimal to binary conversion by aaron_baugher (Curate) on Jun 05, 2015 at 16:12 UTC
Yes, you can drop all the parens when you switch to the ternary operator. And yes, it can be done as a loop, which also removes the 8-bit restriction: `$ cat 1129169.pl #!/usr/bin/env perl use 5.010; use strict; use warnings; sub dec_to_bin { my $dec = shift; print "$dec : "; unless( $dec =~ /^\d+$/ ){ say "Not a whole number!"; return; } my $x = 1; my $bin = ''; while(1){ my $bit = $dec & $x; $bin = ($bit ? 1 : 0) . $bin; $dec -= $bit; last unless $dec; $x <<= 1; } say $bin; } dec_to_bin($_) for @ARGV; $ perl 1129169.pl 0 1 4 255 65536 abc 0 : 0 1 : 1 4 : 100 255 : 11111111 65536 : 10000000000000000 abc : Not a decimal number!` [download] Aaron B. Available for small or large Perl jobs and *nix system administration; see my home node.	[reply] [d/l]