ポインタのソート

明解Ｃ言語入門編 > 12. 構造体 >

PHP

<?php
$NINSU = 5;

function swap(&$x, &$y)
{
    $tmp = $x;
    $x   = $y;
    $y   = $tmp;
}

function compare_height($x, $y)
{
    if ($x["height"] > $y["height"]) return  1;
    if ($x["height"] < $y["height"]) return -1;
    return 0;
}

function compare_weight($x, $y)
{
    if ($x["weight"] > $y["weight"]) return  1;
    if ($x["weight"] < $y["weight"]) return -1;
    return 0;
}

function sort1(&$data, &$ptr, $n, $compare)
{
    $k = $n - 1;
    while ($k >= 0)
    {
        $j = -1;
        for ($i = 1; $i <= $k; $i++)
        {
            if ($compare($data[$ptr[$i - 1]], $data[$ptr[$i]]) > 0)
            {
                $j = $i - 1;
                swap($ptr[$i], $ptr[$j]);
            }
        }
        $k = $j;
    }
}

$data = array();
$data[] = array(name => "Sato",   height => 178, weight => 61.0);
$data[] = array(name => "Sanaka", height => 175, weight => 60.5);
$data[] = array(name => "Takao",  height => 173, weight => 80.0);
$data[] = array(name => "Mike",   height => 165, weight => 72.0);
$data[] = array(name => "Masaki", height => 179, weight => 77.5);

$ptr = array(0, 1, 2, 3, 4);

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

sort1($data, $ptr, $NINSU, "compare_height");

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

sort1($data, $ptr, $NINSU, "compare_weight");

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

print "元の配列：\n";
$i = 1;
function puts($data)
{
    global $i;
    printf("%2d:%-8s%4d%6.1f\n", $i, $data["name"], $data["height"], $data["weight"]);
    $i++;
}
array_walk($data, "puts");
?>

実行結果

L:\>php lesson_12_100.php
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