How can I print integer in triangle form

问题:

I want to print integer in triangle form which look like this

    1
   121
  12321

I tried this but I do not get the actual result

for($i=1;$i<=3;$i++)
 {
    for($j=3;$j>=$i;$j--)
    {
      echo "&nbsp;&nbsp;";
    }
   for($k=1;$k<=$i;$k++)
    {
      echo $k;
    }
   if($i>1)
    {
      for($m=$i; $m>=1; $m--)
         {
           echo $m;
         }
     }      
    echo "<br>";
}

Output of this code is:

   1
  1221
 123321

Where am I going wrong, please guide me.

回答1:

Another integer solution:

$n = 9; 
print str_pad ("✭",$n," ",STR_PAD_LEFT) . PHP_EOL;
for ($i=0; $i<$n; $i++){
    print str_pad ("", $n - $i);
    for ($ii=-$i; $ii<=$i; $ii++){
      if ($i % 2 != 0 && $ii % 2 == 0)
        print "&#" . rand(10025,10059) . ";";
      else print $i - abs($ii) + 1;
    }
    print PHP_EOL;
}

        ✭
        1 
       1✬1 
      12321 
     1❊3✪3✳1 
    123454321 
   1✼3✶5❃5❈3✸1
  1234567654321 
 1✾3✯5✿7❉7✫5✷3✶1 
12345678987654321 

Or if you already have the string, you could do:

$n = 9; $s = "12345678987654321"; $i = 1;

while ($i <= $n)
   echo str_pad ("", $n-$i) . substr ($s,0,$i - 1) . substr ($s,-$i++) . PHP_EOL;

回答2:

Your code should be this:

for($i=1;$i<=3;$i++)
 {
    for($j=3;$j>$i;$j--)
    {
      echo "&nbsp;&nbsp;";
    }
   for($k=1;$k<$i;$k++) /** removed = sign*/
    {
      echo $k;
    }
   if($i>=1) /**added = sign*/
    {
      for($m=$i; $m>=1; $m--)
         {
           echo $m;
         }
     }      
    echo "<br>";
}

Try this.

Details:

1. Your loop is not proper as in case of for($k=1;$k<=$i;$k++), this will print the repeated number when check the condition for less then and again for equals to. So remove the equals sign.

2. reason to add the eqaul sign in if($i>=1) is that the first element will not print if there will not be equals as first it will be print by for loop from where removed the equal sign.

Your output will be this:

   1
  121
 12321

回答3:

For all the x-mas lovers:

$max = 9; # can be 2 .. 9
for($i = 1; $i <= $max; $i++) {
    $line = (str_pad('', $max - $i));
    for($ii = 1; $ii <= $i; $ii++) {
        $line .= $ii;
    }   
    for($ii = $i-1; $ii > 0; $ii--) {
        $line .= $ii;
    }   
    echo $line . PHP_EOL;
}

Output:

        1
       121
      12321
     1234321
    123454321
   12345654321
  1234567654321
 123456787654321
12345678987654321

Amazing what computers are able to achieve nowadays! Isn't it?

回答4:

A little late to the party, but here's yet another solution that uses a "for" loop with two initialization variables and a ternary-based incrementer/decrementer. It's an unorthodox use of a "for" loop, but it's still perfectly valid and arguably makes the code more elegant and easier to follow. I chose to add space before and after each semicolon and omit all other space inside the parentheses so it's easier to visualize each of the three pieces of the "for" loop (initialization, condition, increment/decrement):

$count = 9;
echo "<pre>";
for ($i=1; $i<=$count; $i++) {
    echo str_pad("",$count-$i," ",STR_PAD_LEFT);
    for ( $j=1,$up=true ; $j>0 ; $up?$j++:$j-- ) {
        echo $j;
        if ($j==$i) {$up = false;}
    }
    echo "<br>";
}
echo "</pre>";

Output:

        1
       121
      12321
     1234321
    123454321
   12345654321
  1234567654321
 123456787654321
12345678987654321