zanex/ITL2-Primzahlen
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Fixed up a few last things.

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This commit is contained in:
Elias F.
2025-11-17 15:38:40 +01:00
parent 84fda1c315
commit b19fdf4bb0
1 changed files with 32 additions and 31 deletions
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59
index.php
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@@ -2,15 +2,11 @@
<html lang="en"> <html lang="en">
<head> <head>
<meta charset="UTF-8"> <meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1"> <meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Primzahlen</title> <title>Primzahlen</title>
<style> <style>
.wrapper { .wrapper { display: flex; gap: 20px; }
display: flex; .mono { font-family: monospace; white-space: pre; }
flex-direction: row;
gap: 20px;
}
</style> </style>
</head> </head>
<body> <body>
@@ -19,38 +15,38 @@
<div> <div>
<form action="index.php" method="post"> <form action="index.php" method="post">
<label>Input: <label>Input:
<input type="number" name="input"> <input type="number" name="input" min="2" required>
</label> </label>
<button type="submit">Berechnen</button> <button type="submit">Berechnen</button>
</form> </form>
<?php <?php
if(isset($_POST['input'])) { if ($_SERVER['REQUEST_METHOD'] === 'POST' && isset($_POST['input'])) {
$primeNumbers = [];
$max = (int) $_POST['input']; $max = (int) $_POST['input'];
if ($max < 2) {
for($i = 0; $i <= $max; $i++) { echo "<p>Bitte eine Zahl >= 2 eingeben.</p>";
if(isPrime($i)) { } else {
$primeNumbers = [];
for ($i = 2; $i <= $max; $i++) {
if (isPrime($i)) {
$primeNumbers[] = $i; $primeNumbers[] = $i;
} }
} }
echo "<h3>Primzahlen von " . htmlspecialchars($_POST["input"], ENT_QUOTES, 'UTF-8') . " sind:</h3>"; $safe = htmlspecialchars((string)$_POST['input'], ENT_QUOTES, 'UTF-8');
echo "<h3>Primzahlen von 1 bis {$safe}:</h3>";
foreach($primeNumbers as $number) { echo "<p>" . implode(", ", $primeNumbers) . "</p>";
echo "<span>" . $number . "</span><br>";
} }
} }
function isPrime($i) { function isPrime(int $n): bool {
if ($i <= 1) return false; if ($n <= 1) return false;
if ($i <= 3) return true; if ($n <= 3) return true;
if ($i % 2 == 0) return false; if ($n % 2 === 0) return false;
for ($j = 3; $j * $j <= $i; $j += 2) { $limit = (int) floor(sqrt($n));
if ($i % $j == 0) { for ($d = 3; $d <= $limit; $d += 2) {
return false; if ($n % $d === 0) return false;
}
} }
return true; return true;
@@ -64,12 +60,17 @@
<?php <?php
for ($n = 1; $n <= 100; $n++) { for ($n = 1; $n <= 100; $n++) {
$ln = log($n); $ln = log($n);
$lnFormatted = number_format($ln, 4, '.', ''); $rounded = round($ln * 2) / 2;
$full = (int) floor($rounded);
$half = ($rounded - $full) >= 0.5 ? 1 : 0;
$starsCount = (int) floor($ln); if ($full === 0 && $half === 0) {
$stars = $starsCount > 0 ? str_repeat('*', $starsCount) : '-'; $visual = '-';
} else {
$visual = str_repeat('*', $full) . ($half ? '+' : '');
}
echo sprintf("%3d: ln=%6s %s<br>", $n, $lnFormatted, $stars); echo str_pad($n, 3, ' ', STR_PAD_LEFT) . ": " . $visual . "<br>";
} }
?> ?>
</div> </div>