for(@input){
    if($_[1] gt $_[2]){
    push (@output, "$_[0] $_[2] $_[1] $[3] +");
}

print "$_\n" for @output;

##</code><code>##

use strict;
use warnings;

my @input;
my @output;

while (<DATA>) {
    push @input, $_;
}
for (@input) {
    my @temp = split( /\s+/, $_ ); # you split on a delimiter, which is 1 or more spaces in this case

    if ( $temp[1] gt $temp[2] ) {
        push( @output, "$temp[0] $temp[2] $temp[1] $temp[3] +" );
    }
    else {
        push @output, "$temp[0] $temp[1] $temp[2] $temp[3]";
    }
}

print "$_\n" for @output

__DATA__
red 15 2 smith
blue 4 10 walter