ポインタのソート

明解Ｃ言語入門編 > 12. 構造体 >

Perl

$NINSU = 5;

sub swap
{
    my ($x, $y) = @_;
    
    $tmp = $$x;
    $$x  = $$y;
    $$y  = $tmp;
}

sub compare_height
{
    my ($x, $y) = @_;

    return  1 if ($$x->{"height"} > $$y->{"height"});
    return -1 if ($$x->{"height"} < $$y->{"height"});
    return 0;
}

sub compare_weight
{
    my ($x, $y) = @_;

    return  1 if ($$x->{"weight"} > $$y->{"weight"});
    return -1 if ($$x->{"weight"} < $$y->{"weight"});
    return 0;
}

sub sort
{
    my ($data, $ptr, $n, $compare) = @_;
    
    $k = $$n - 1;
    while ($k >= 0)
    {
        $j = -1;
        foreach $i(1..$k)
        {
            if ($compare->(\$$data[$ptr[$i - 1]], \$$data[$ptr[$i]]) > 0)
            {
                $j = $i - 1;
                &swap(\$$ptr[$i], \$$ptr[$j]);
            }
        }
        $k = $j;
    }
}


@data = ();
push(@data, {name => "Sato",   height => 178, weight => 61.0});
push(@data, {name => "Sanaka", height => 175, weight => 60.5});
push(@data, {name => "Takao",  height => 173, weight => 80.0});
push(@data, {name => "Mike",   height => 165, weight => 72.0});
push(@data, {name => "Masaki", height => 179, weight => 77.5});

@ptr = (0..4);

print "ソ\ート前：\n";
for (0..$NINSU-1)
{
    printf("%2d:%-8s%4d%6.1f\n", $_ + 1, $data[$ptr[$_]]{"name"}, $data[$ptr[$_]]{"height"}, $data[$ptr[$_]]{"weight"});

}
print "\n";

&sort(\@data, \@ptr, \$NINSU, \&compare_height);

print "身長でソ\ート後：\n";
for (0..$NINSU-1)
{
    printf("%2d:%-8s%4d%6.1f\n", $_ + 1, $data[$ptr[$_]]{"name"}, $data[$ptr[$_]]{"height"}, $data[$ptr[$_]]{"weight"});
}
print "\n";

&sort(\@data, \@ptr, \$NINSU, \&compare_weight);

print "体重でソ\ート後：\n";
for (0..$NINSU-1)
{
    printf("%2d:%-8s%4d%6.1f\n", $_ + 1, $data[$ptr[$_]]{"name"}, $data[$ptr[$_]]{"height"}, $data[$ptr[$_]]{"weight"});
}
print "\n";

print "元の配列：\n";
$i = 1;
map { printf("%2d:%-8s%4d%6.1f\n", $i, $_->{"name"}, $_->{"height"}, $_->{"weight"}); $i++; } @data;

実行結果

L:\>perl lesson_12_100.pl
ソート前：
1:Sato 178 61.0
2:Sanaka 175 60.5
3:Takao 173 80.0
4:Mike 165 72.0
5:Masaki 179 77.5

身長でソート後：
1:Mike 165 72.0
2:Takao 173 80.0
3:Sanaka 175 60.5
4:Sato 178 61.0
5:Masaki 179 77.5

体重でソート後：
1:Sanaka 175 60.5
2:Sato 178 61.0
3:Mike 165 72.0
4:Masaki 179 77.5
5:Takao 173 80.0

元の配列：
1:Sato 178 61.0
2:Sanaka 175 60.5
3:Takao 173 80.0
4:Mike 165 72.0
5:Masaki 179 77.5