﻿ PHP: Check a sequence of numbers is an arithmetic progression or not - w3resource

# 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 :

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 Code Editor:

```<?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");
?>
```

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