PHP计算年龄

31,
2 => 28,
3 => 31,
4 => 30,
5 => 31,
6 => 30,
7 => 31,
8 => 31,
9 => 30,
10 => 31,
11 => 30,
12 => 31
);
$y = $m = $d = 0;
//天相减为正
if ($time['mday'] >= $birthday['mday']) {
//月相减为正
if ($time['mon'] >= $birthday['mon']) {
$y = $time['year'] - $birthday['year'];
$m = $time['mon'] - $birthday['mon'];
} else {
//月相减为负，借年
$y = $time['year'] - $birthday['year'] - 1;
$m = $time['mon'] - $birthday['mon'] + 12;
}
$d = $time['mday'] - $birthday['mday'];
return ($y == 0 ? '' : $y . '岁') . ($m == 0 ? '' : $m . '个月') . ($d == 0 || $y > 0 ? '' : $d . '天');
}
//天相减为负，借月
if ($time['mon'] == 1) { //1月，借年
$y = $time['year'] - $birthday['year'] - 1;
$m = $time['mon'] - $birthday['mon'] + 12;
$d = $time['mday'] - $birthday['mday'] + $monthDays[12];
return ($y == 0 ? '' : $y . '岁') . ($m == 0 ? '' : $m . '个月') . ($d == 0 || $y > 0 ? '' : $d . '天');
}
//3月，判断闰年取得2月天数
if ($time['mon'] == 3) {
$d = $time['mday'] - $birthday['mday'] + ($time['year'] % 4 == 0 ? 29 : 28);
} else {
$d = $time['mday'] - $birthday['mday'] + $monthDays[$time['mon'] - 1];
}
//借月后，月相减为正
if ($time['mon'] >= $birthday['mon'] + 1) {
$y = $time['year'] - $birthday['year'];
$m = $time['mon'] - $birthday['mon'] - 1;
} else {
//借月后，月相减为负，借年
$y = $time['year'] - $birthday['year'] - 1;
$m = $time['mon'] - $birthday['mon'] + 12 - 1;
}
return ($y == 0 ? '' : $y . '岁') . ($m == 0 ? '' : $m . '个月') . ($d == 0 || $y > 0 ? '' : $d . '天');
}
var_dump(datediffage($birthday, $time));