FInd Missing number and MIN and MAX Value and find Dublicate values count WITHOUT using PHP inbuild functions.Checked many but no suitable for me

I am having below array

$inputArray = array(1, 2, 5, 7,2);

• Now i want to find MIN and MAX Values.
• Second Thing find missing values in this array
• Third dublicate number count, How can i acheive this,pls anyone
  help me here.

my code

$inputArray = array(1, 2, 5, 7,2);
$min = 0;
$max = 0;
foreach($inputArray as $inputValue){
    if ($inputValue >= $min) { 
       $max = $inputValue; // maximum value
    }
}

foreach($inputArray as $inputValue){
    if ($max >= $inputValue) { 
       $min = $inputValue; // minimum value
    }
}
echo $max;

Note: Mainthing we should not use single PHP inbuild functions.

>Solution :

$inputArray = array(1, 2, 5, 7,2);
$i=0;
foreach($inputArray as $inputValue){
   if($i == 0){
      $min = $inputValue;
      $max = $inputValue;
   }
   if($inputValue > $max){
      $max = $inputValue;
   }
   if($inputValue < $min){
      $min = $inputValue;
   }
   $i +=1;
}
echo $i ."<br>"; // array count

echo $min ."<br>";

echo $max ."<br>";