println [[1..<5],[5..1]].flatten().collect { n -> ''.padLeft(n, '*') }.join('\n')

<?php

function print_stars($num) {
        while ($i < $num) {
                echo "*";
                $i++;
        }
}

$STARS = 5;

for ($i = 1; $i <= $STARS; $i++) {
        print_stars($i);
        echo "<br>";
}

for ($i = $STARS-1; $i >= 1; $i--) {
        print_stars($i);
        echo "<br>";
}

?>

procedure TApp.Example1;
var
  i, j, d: integer;
  s: string;
begin

  // param check
  if paramcount<1 then
  begin
    Writeln('usage: Example1 [amount of stars]');
    Terminate;
    Exit;
  end;

  // init vars
  trystrtoint(paramstr(1), i);
  s:= '';
  d:= i*2;

  // do stars
  for j:=0 to d-1 do
  begin
    if (j<i) then
    begin
      s:= s + '*';
    end else
    begin
      setlength(s, d-j-1);
    end;
    writeln(s);
  end;

end;

int main()
{
  int n = 60;
  for(int i=0; i<=(n%2?n*2-1:n*2); i++)
  {
    for(int j=0; j<(i - i/(n+1) * ((i - n)*2)); j++)
    {
      cout << "*";
    }
    cout << endl;
  }
}

def tahdet(n):
    return '\n'.join('*' * x for x in range(1, n) + range(n, 0, -1))

print tahdet(5)

<script>
var stars = 5,
  pyramides = 1,
  char = "*",
  delimiter = "",

  i=0, l= pyramides*2, str ="";

for (;i<l;i++) {
  var lines = stars;
  
  while (lines--) {
    str = (i % 2) ? str.substr(1) : str+char;
    (str.length) ? console.log(str) : (i+1<l) ? console.log(delimiter) : "";
  }
}
</script>

$d = 5;
for(1..$d*2) {
    print "\n";
    if($_ < $d+1) {
        for(1..$_) { print "*"; }
    } else {
        for(1..($d*2-$_)) { print "*"; }
   }
}

: stars 0 do 42 emit loop cr ;  ok
: rise 1+ 1 do i stars loop ;  ok
: fall 1- 1 swap do i stars -1 +loop ;  ok
: pattern dup cr rise fall ;  ok
  ok
5 pattern 
*
**
***
****
*****
****
***
**
*
 ok

    private static void piirra(int korkeus) {
        String tahdet="";
        
        for (int i=0; i < korkeus; ++i) {
            tahdet += "*";
            System.out.println(tahdet);
        }
        kaanna(tahdet);
    }

    private static void kaanna(String tahdet) {
        if (tahdet.length() == 0)
            return;
        
        tahdet = tahdet.substring(0, tahdet.length()-1);
        System.out.println(tahdet);
        kaanna(tahdet);
    }

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            int stars = 6; // int.Parse(Console.ReadLine());

            1.To(stars).And((stars - 1).To(1)).Do((i) => Console.WriteLine(new string('*', i)));
        }
    }

    static class Extensions
    {
        public static void Do<T>(this IEnumerable<T> enumerable, Action<T> action)
        {
            foreach (var item in enumerable)
                action(item);
        }

        public static IEnumerable<int> To(this int from, int to)
        {
            if (to < from)
                return Enumerable.Range(to, from + 1 - to).Reverse();
            else
                return Enumerable.Range(from, to + 1 - from);
        }

        public static IEnumerable<int> And(this IEnumerable<int> coll1, IEnumerable<int> coll2)
        {
            return coll1.Concat(coll2);
        }
    }
}

bwBASIC: list
     10: input k
     20: for i=1 to k
     30: gosub 100
     40: next i
     50: for i=k-1 to 1 step -1
     60: gosub 100
     70: next i
     80: end
    100: for j=1 to i
    110: print "*";
    120: next j
    130: print
    140: return
bwBASIC: run
? 5
*
**
***
****
*****
****
***
**
*
bwBASIC:

Public Sub WriteStars()
    Dim NumberOfStarsInLongestLine As Integer
    Dim Stars As String
    
    NumberOfStarsInLongestLine = 5
    
    For counter = 1 To NumberOfStarsInLongestLine
        Stars = Stars & vbCrLf & String(counter, "*")
    Next counter
        
    For counter = NumberOfStarsInLongestLine - 1 To 1 Step -1
        Stars = Stars & vbCrLf & String(counter, "*")
    Next counter
    
    MsgBox Stars

End Sub

$ cat stars.for

      INTEGER I,K

      READ *,K
      DO 100 I=1,K
      CALL STAR(I)
  100 CONTINUE
      DO 200 I=1,K
      CALL STAR(K-I)
  200 CONTINUE
      STOP
      END

      SUBROUTINE STAR(N)
      INTEGER N
      INTEGER J
      DO 300 J=1,N
      WRITE(*,'(A,$)') '*'
  300 CONTINUE
      WRITE(*,'(A)') ' '
      END

$ f77 stars.for
   MAIN:
   star:
$ ./a.out
5
* 
** 
*** 
**** 
***** 
**** 
*** 
** 
*

#!/bin/sh

STARS=$1

for i in `seq 1 1 $STARS ;seq $(($STARS - 1)) -1 1`
do 
    for j in `seq $i`
    do
    echo -n "*"
    done
    echo
done

$ ./stars.sh 5
*
**
***
****
*****
****
***
**
*

def print_stars(len)
  1.upto(len-1) { |counter| puts '*'*counter }
  len.downto(1) { |counter| puts '*'*counter }
end

print_stars(5);

object Yhyy {
  def main(args:Array[String]) = {
    var numero:Int = args(0).toInt
    for (i <- 0 until numero) {
        tulostaaah(i, 0)
    }
    for (i <- (1 to (numero - 1)).reverse){
        tulostaaah(i, 1)
    }
  }
  
  def tulostaaah(a: Int, b: Int){
    var juu = ""
    for(i <- b to a){
        juu += "*"
    }
    println(juu)
  }
}

E:\ohjelmointi\scala\tmp>scala Yhyy 5
*
**
***
****
*****
****
***
**
*

(defn stars [x] (doseq [_ (range x)] (print \x)))
(defn triangle [width]
    (doseq [x (concat (range 1 width) (range width 0 -1))]
      (stars x) (println)))

user=> (triangle 5)
x
xx
xxx
xxxx
xxxxx
xxxx
xxx
xx
x