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PHP Challenges: Check a sequence of numbers is an arithmetic progression or not

PHP Challenges - 1: Exercise-15 with Solution

Write a PHP program to check a sequence of numbers is an arithmetic progression or not.

Input : array(5, 7, 9, 11)

In mathematics, an arithmetic progression or arithmetic sequence is a sequence of numbers such that the difference between the consecutive terms is constant.
For example, the sequence 5, 7, 9, 11, 13, 15 ... is an arithmetic progression with common difference of 2.

Explanation :

PHP: Check a sequence of numbers is an arithmetic progression or not

Sample Solution :

PHP Code :

<?php
function is_arithmetic($arr)
  {
   $delta = $arr[1] - $arr[0];
   for($index=0; $index<sizeof($arr)-1; $index++)
    {
        if (($arr[$index + 1] - $arr[$index]) != $delta)
        {
             
             return "Not an arithmetic sequence";
        }       
    }
    return "An arithmetic sequence";
}
$my_arr1 = array(6, 7, 9, 11);
$my_arr2 = array(5, 7, 9, 11);

print_r(is_arithmetic($my_arr1)."\n");
print_r(is_arithmetic($my_arr2)."\n");
?>

Sample Output:

Not an arithmetic sequence                                  
An arithmetic sequence  

Flowchart:

PHP Flowchart: Check a sequence of numbers is an arithmetic progression or not

PHP Code Editor:

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Previous: Write a PHP program to reverse the bits of an integer (32 bits unsigned).
Next: Write a PHP program to check a sequence of numbers is a geometric progression or not.

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