CODEWITHSUNDEEP
php
Shakun Chaudhary
Shakun Chaudhary

Reputation: 339

Reverse a string in php without using any string function

In yesterday Interview I was asked that how to reverse a string with out using any string function like strrev() or strlen(). I found this example on website but it gives error.is it possible to do this without strlen().

Uninitialized string offset: -1 in D:\xampp\htdocs\PhpProject1\index.php on line xx

$string = "ZEESHAN";

$i =0;

while(($string[$i])!=null){

        $i++;

}

$i--;

while(($string[$i])!=null){

        echo $string[$i];

$i--;

}

Upvotes: 4

Views: 43289

Answers (12)

Shakeel Ahmad
Shakeel Ahmad

Reputation: 349

With a minor modifications

<?php

  $string = "Hello";
  $reverse = "";
  $i = 0;
  while($i < strlen($string)){
    $reverse = $string[$i].$reverse;
    $i++;
  }
  echo $reverse;

?>

Upvotes: 0

Nivedan Sharma
Nivedan Sharma

Reputation: 1

Check this code to resolve this problem.

<?php

$string = "ZEESHAN";

$i =0;

while(!empty($string[$i])){ 
       
        $i++;
}

$i--;

while(!empty($string[$i])){     

        echo $string[$i];

$i--;

}

?>

Upvotes: 0

Rakesh
Rakesh

Reputation: 1

<?php
$string = 'ZEESHAN';
$reverse = '';
$i = 0;
while(!empty($string[$i])){
    $reverse = $string[$i].$reverse;
    $i++;
}
echo $reverse;
?>

Check complete post: https://www.troposal.com/reverse-string-without-function-php/

Upvotes: -1

ABHISHEK GUPTA
ABHISHEK GUPTA

Reputation: 71

//Program for reversing a string
<?php
class str_rev{
    public function Revese_Str($string){
        $reverse = '';
        $i=0;
        while(!empty($string[$i])){ 
          $reverse = $string[$i].$reverse; 
          $i++;
        }
        return $reverse;
    }
}
$object = new str_rev();
echo $object->Revese_Str('Ayush Jain');

Upvotes: 0

Ashu Jha
Ashu Jha

Reputation: 344

I have created a simple logic for string reversal

$str = 'ABCD';
$strReversed = '';
$length = strlen($str);
for($i=$length-1; $i >= 0; $i--){
    $strReversed .= $str[$i];
}
echo $strReversed;

Upvotes: 1

user1452914
user1452914

Reputation:

Please take a look the below code: Reverse the string

$str = 'abcdefg';
    $reverseString = '';
    for($i=strlen($str);$i<=strlen($str);$i--){
      $reverseString .= $str[$i];
    if($i==0)
    break;
    }

    echo $reverseString;

The above code output is:

gfedcba

Upvotes: -1

Suhail MuRad
Suhail MuRad

Reputation: 1

<!doctype html>
<html>
  <body>
    <center>
      <form action="#" method="get">
        <br>
        <input type="text" name="txt"/>
        <br><br>
        <input type="submit" name="submit"/>
        <br><br>
      </form>

<?php
if(isset($_GET["submit"])) {
    $name = $_GET["txt"];
    for ($i = 0; isset($name[$i]); $i++) {
        $j = $i;
    }
    for ($k = $j; isset($name[$k]); $k--) {
        echo $name[$k];
    }
}

Upvotes: -1

Kheshav Sewnundun
Kheshav Sewnundun

Reputation: 1244

You can try it with count_chars and array_sum

<?php

$string = "ZEESHAN";
$count=array_sum(count_chars($string));

for($i=$count -1 ;$i>=0;$i--){
        echo $string[$i];
}
?>

If you dont want any php string function you can try this way with krsort and array:

<?php

$string = "ZEESHAN";
$arr = array();
$i=0;
while(isset($string[$i])){
        $arr[$i] = $string[$i];
        $i++;
}
krsort($arr);
$final = implode("",$arr);

var_dump($final);
?>

Upvotes: 0

Sougata Bose
Sougata Bose

Reputation: 31749

Try -

$string = "ZEESHAN";

$j = 0;
while(!empty($string[$j])) {
   $j++;
}

for($i = ($j-1); $i >= 0; $i--) {
    echo $string[$i];
}

Output

NAHSEEZ

Upvotes: 1

Miguel
Miguel

Reputation: 1897

You can do this

$string = "heya";
$i = strlen("heya") - 1;
$newStr = "";

while($i >= 0) {
    $newStr .= $string[$i];
    $i--;
}
echo $newStr; // output: ayeh

Upvotes: -1

Narendrasingh Sisodia
Narendrasingh Sisodia

Reputation: 21437

You can use while and for loop like as

$string = "ZEESHAN";
$reverse = "";
$j = 0;
while(isset($string[$j])){
    $j++;
}

for($i = $j - 1; $i >= 0; $i--){
    $reverse .= $string[$i];
}
echo $reverse;

Upvotes: 0

Surace
Surace

Reputation: 711

$string = 'zeeshan';
$reverse = '';
$i = 0;
while(!empty($string[$i])){ 
      $reverse = $string[$i].$reverse; 
      $i++;
}
echo $reverse;

Upvotes: 17

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