Code explanation of the formula for string formatting in PHP using eval

Sometimes we have a commission formula for each product, and the formula for calculating the Commission is in the form of a string, and when we use this formula, he is not like we wrote: $a =2+3*5; so it's simple to calculate the result, and it's a string, so We have to translate the string into the results we can handle.

Sometimes we have a commission formula for each product, and the formula for calculating the Commission is in the form of a string, and when we use this formula, he does not write as we do: $a =2+3*5; So simple as to calculate the result, And it's a string. So, we have to translate the string into the result we can handle.
The eval () function in PHP can handle PHP code, so this can be used to solve: A calculation formula stored in a string format

Like what:

$str = ' 3+12 '; $result =eval ("return $str;"); echo $result;

Will output: 30

Is the value of an expression

Where the return $str in eval () is the PHP code

The value of the variable can also be brought in:

$a =3; $b =12; $str = ' ($a + $b) '; $result =eval ("return $str;"); echo $result;

Will output: 30

This implementation of the PHP implementation of the calculator code, mainly using the PHP eval function.

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