# php – How to convert number in billions to a smaller comparison chain?

## Question:

Suppose you have an exercise in the following aspect, I need to take from an array with random integers, the largest number that is between the ranges.

For example, I have an array: `array(2, 8, 4);`

1. would have to order: 2,4,8

2. check the range from 2 to 4 = 2, and from 4 to 8 = 4

3. the largest interval, in this case, would be 4 , between 4 and 8.

Starting from this idea, I have the following code structure:

``````<?php

class VerifyNumbers
{

private \$arr = array();

public function __construct(array \$arr)
{
\$this->arr = \$arr;
}

public function verifyMaxIntersectionFromArray()
{
\$collection = array();

sort(\$this->arr);

for (\$i= 0; \$i < count(\$this->arr); \$i++) {
if (isset(\$this->arr[\$i + 1])) {
\$collection[] = (\$this->arr[\$i + 1] - \$this->arr[\$i]);
}
}
return max(\$collection);
}

}

\$verifyNumber = new VerifyNumbers(array(100, 3000, 4000, 25, 540, 20, 200, 300));
\$maxIntersection = \$verifyNumber->verifyMaxIntersectionFromArray();

echo \$maxIntersection;
``````

The question I ask is, and if in this case, I had input values ​​in this array that exceeded the 4 billion place, or even greater, because there could be negative numbers, which would double, the range, how could I convert these numbers input in a smaller, readable string, since in PHP 5, an invalid digit is passed to an octal integer (eg 8 or 9), the rest of the number will be ignored.

You must format the number. Let's imagine that `\$num` is the variable of the number I want to format:
``````echo "O seu número formatado é: ". number_format(\$num, 4);
What's in front of the `\$num` is how many places this number is going to have. So, in that case, instead of being for example 1.000000 it's going to be 1.0000!