Php 3个字符的打印图案序列

我想用PHP打印3个字符的图案。像aaa，aab，aac。。。。zzz

现在，我正在使用这些PHP代码，但它是随机打印的，而不是按顺序打印的

$i = 1; 
$chars = array("a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p","q","r","s","t","u","v","w","x","y","z");

while($i > 0){ $current = $chars[rand(0,25)].$chars[rand(0,25)].$chars[rand(0,25)]; }

草率

$i=0;
$j=0;
$k=0;
while($i<26){
  while($j<26){
    while($k<26){
      echo $chars[$i] . $chars[$j] . $chars[$k];
      $k++;
    }
    $j++;
    $k=0;
  }
  $i++;
  $j=0;
  $k=0;
}

$i=0；
$j=0；
$k=0；
而（$i从0到26^3-1进行计数。然后将数字转换为以26为基数，根据需要将数字替换为字母，如果转换结果为一位数或两位数，则前缀为“a”或“aa”

使用此函数：string base_convert（string$number，int$frombase，int$tobase）

我不会为您编写所有代码。您需要从中学习。
如果您需要随机打印，如“aaa”或“vvv”或“ddd”，请尝试使用

$char = $chars[rand(0,25)]; 
echo $current = $char.$char.$char;

如果要打印“aaa”、“bbb”、“ccc”…-请使用

for ($i = 0; $i < 26; $i++) {
    $char = $chars[$i]; 
    echo $current = $char.$char.$char;
}

（$i=0；$i<26；$i++）的
{
$char=$chars[$i]；
echo$current=$char.$char.$char；
}
我是用c#写的

分析错误：语法错误，在C:\xampp\htdocs\start\test2.php的第12行出现意外的“[”，应为“，”或“；”，但当我将“echo chars[$i].chars[$j].chars[$k]；”替换为“echo”hi
；“然后打印hi”。@RinkuYadav确定，然后尝试，看看是否修复了任何问题：echo“chars[$i]chars[$j]chars[$k]
”；@RinkuYadav oops刚刚意识到了这一点，忘记了字符前面的“$”，它正在打印正确的数组序列，但当我使用echo chars[$i].chars[$j].chars[$k]；然后它显示错误解析错误：语法错误，意外[”，应为“，”或“；”。我可以打印字符而不是数组吗？我需要序列而不是随机。请再次阅读问题。
        string sample = "AAA";
        char[] chars = sample.ToCharArray();

        char first = chars[0];
        char second = chars[1];
        char third = chars[2];

        if (first == second && first == third)
        {
            third++;
            bool isAlphaBet = Regex.IsMatch(third.ToString(), "[a-z]", RegexOptions.IgnoreCase);
            if (isAlphaBet)
            {
                return $"{first}{second}{third}";
            }
            return $"empty";
        }
        if (first == second && first != third)
        {
            third++;
            bool isAlphaBet = Regex.IsMatch(third.ToString(), "[a-z]", RegexOptions.IgnoreCase);
            if (isAlphaBet)
            {
                return $"{first}{second}{third}";
            }
            else
            {
                second++;
                third = 'A';

                return $"{first}{second}{third}";
            }
        }//"ABA";
        if (first != second && first == third)
        {
            third++;

            bool isAlphaBet = Regex.IsMatch(third.ToString(), "[a-z]", RegexOptions.IgnoreCase);
            if (isAlphaBet)
            {
                return $"{first}{second}{third}";
            }
            else
            {
                second++;
                third = 'A';

                return $"{first}{second}{third}";
            }
           
        }
        if (first != second && first != third && second != third)
        {
            third++;

            bool isAlphaBet = Regex.IsMatch(third.ToString(), "[a-z]", RegexOptions.IgnoreCase);
            if (isAlphaBet)
            {
                return $"{first}{second}{third}";
            }
            else
            {
                second++;
                third = 'A';
                bool isAlphaBetSecond = Regex.IsMatch(second.ToString(), "[a-z]", RegexOptions.IgnoreCase);
                if (isAlphaBetSecond)
                {
                    return $"{first}{second}{third}";
                }
                else
                {
                    second = 'A';
                    first++;
                    bool isAlphaBetFirst = Regex.IsMatch(first.ToString(), "[a-z]", RegexOptions.IgnoreCase);
                    if (isAlphaBetFirst)
                    {
                        return $"{first}{second}{third}";
                    }
                    else
                    {
                        return $"empty";
                    }
                }
              
            }

        }
        if (first != second && second == third)
        {
            third++;
            bool isAlphaBetThird = Regex.IsMatch(third.ToString(), "[a-z]", RegexOptions.IgnoreCase);
            if (isAlphaBetThird)
            {
                return $"{first}{second}{third}";
            }
            else
            {
                third = 'A';
                second++;
                bool isAlphaBetSecond = Regex.IsMatch(second.ToString(), "[a-z]", RegexOptions.IgnoreCase);
                if (isAlphaBetSecond)
                {
                    return $"{first}{second}{third}";
                }
                else
                {
                    second = 'A';
                    first++;
                    bool isAlphaBetFirst = Regex.IsMatch(first.ToString(), "[a-z]", RegexOptions.IgnoreCase);
                    if (isAlphaBetFirst)
                    {
                        return $"{first}{second}{third}";
                    }
                    else
                    {
                        return $"empty";
                    }
                }
            }
        }

        return $"{first}{second}{third}";