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What is the daffodil number in php

藏色散人

Sep 16, 2019 pm 02:56 PM

php

phpWhat is the number of daffodils?

The so-called "daffodil number" refers to an n-digit number (n≥3), the sum of the nth power of the numbers in each digit is equal to itself.

PHP program for finding the number of daffodils, there are many ways to write it:

Method Example 1:

<?php
header("content-type:text/html;charset=utf-8;"); //设置页面编码为 utf-8
//以下代码求解1000以内的水仙花数
echo &#39;<p>1000以内的水仙花数: </p>&#39;;
for ( $i = 100; $i < 1000; ++ $i )
{
    $hundreds = floor( $i / 100);    //分解出百位
    $tens = floor( $i / 10 ) % 10;   //分解出十位
    $ones = floor( $i % 10 );        //分解出个位
    if (bcpow($hundreds,&#39;3&#39;)+bcpow($tens,&#39;3&#39;)+bcpow($ones,&#39;3&#39;) == $i)
        echo $i."";
}
?>

Output:

1000以内的水仙花数:
153
370
371
407

Method example two:

<?php
for($q=1;$q<=9;$q++){
    for($w=0;$w<=9;$w++){
        for($e=0;$e<=9;$e++){
            if($q*$q*$q + $w*$w*$w + $e*$e*$e ==
                100*$q + 10*$w + $e){
                echo "$q$w$e"."<p>";
            }
        }
    }
}

Output:

Method example three:

<?php
function cube( $n )
{
    return $n * $n * $n;
}

function is_narcissistic ( $n )
{
    $hundreds = floor( $n / 100);    //分解出百位
    $tens = floor( $n / 10 ) % 10;    //分解出十位
    $ones = floor( $n % 10 );    //分解出个位
    return (bool)(cube($hundreds)+cube($tens)+cube($ones) == $n);
}


for ( $i = 100; $i < 1000; ++ $i )
{
    if ( is_narcissistic($i) )
        echo $i."\n";
}

Method example four :

<?php
//阿姆斯特朗数：一个k位数，它的每个位上的数字的k次幂之和等于它本身。（例如：1^3 + 5^3 + 3^3 = 153）
class Armstrong {
    static function index(){
        for ( $i = 100; $i < 100000; $i++ ) {
            echo self::is_armstrong($i) ? $i . &#39;<br>&#39; : &#39;&#39;;
        }
    }
    static function is_armstrong($num){
        $s = 0;
        $k = strlen($num);
        $d = str_split($num);
        foreach ($d as $r) {
            $s += bcpow($r, $k);
        }
        return $num == $s;
    }
}
Armstrong::index();

Output:

Method example five:

<html>
<head>
<title></title>
</head>
<body>
<?php
function winter($num)
{
if($num<1000){
//定义个位
$ge=$num%10;
//定义十位
$ten=(($num%100)-$ge) /10;
//定义百位
/*floor取整，忽略小数点后面的所有数*/
$hundred=floor($num/100);
$sum1=$ge*$ge*$ge+$ten*$ten*$ten+$hundred*$hundred*$hundred;
if($sum1==$num){
return 1;
} else{
return 0;
}
} else{
return -1;
}
}
if(winter(371)==-1) {
echo "大于1000的数";
}else{
if(winter(371)) {
echo "Yes";
}
else{
echo "No";
}
}
?>
</body>
</html>

Output:

Yes

Related recommendations: " PHP Tutorial》

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