Exact division using fdiv() function in PHP8

With the continuous development of computer technology, number operations have become one of the most basic and important contents in computers. However, when performing division operations of floating-point numbers, large errors may occur due to the accuracy of computer storage of floating-point numbers. In order to solve this problem, the fdiv() function was added in PHP8 for precise division operations.

The syntax format of the fdiv() function is:

fdiv(float $dividend, float $divisor): float

Among them, $dividend represents the dividend, $divisor represents the divisor, and the return value is the result of the division operation, that is, $dividend divided by $divisor The exact value.

Next, let’s look at some specific usage examples.

1. General division operation

When performing division operation, we usually use the division operator "/" to complete it. For example, if we need to calculate the result of dividing 10 by 3, we can use the following code:

$result = 10 / 3;
echo $result; // 3.3333333333333

Looking at the value of $result, we will find that the result is 3.3333333333333. This is due to accuracy issues when computers store floating point numbers. of.

If you use the fdiv() function to perform the same operation, the code is as follows:

$result = fdiv(10, 3);
echo $result; // 3.3333333333333

It seems that there is no change, but in fact the fdiv() function performs a more precise operation to ensure to get more accurate results.

2. Handling the boundary cases of floating-point numbers

When dealing with floating-point division, you often encounter some extreme situations, such as the divisor is 0, the divisor is extremely small, etc. In these cases, regular division operations may cause program exceptions or erroneous results.

For the case where the divisor is 0, a DivideByZeroError exception will be thrown in PHP, so the program needs to perform exception handling. For example:

try {
    $result = fdiv(10, 0);
} catch (DivideByZeroError $e) {
    echo "Error: Cannot divide by 0";
}

For cases where the divisor is very small, inaccurate results may be obtained due to the precision limit of floating point numbers stored in the computer. In this case, you can improve the accuracy of the calculation by setting the precision. For example, we set the calculation result to retain 20 decimal places:

ini_set('precision', 20);
$result = fdiv(10, 0.0000001);
echo $result; // 1.0E+8

You can see that by setting the precision, we get more accurate calculation results.

3. Division operations for handling very large numbers

When dealing with very large numbers, using regular division operations often produces very large errors. At this time, you can use the precise calculation function of the fdiv() function to perform precise division operations on extremely large numbers. For example, we need to calculate the result of dividing 2 to the power of 100 by 3:

$dividend = pow(2, 100);
$divisor = 3;
$result = fdiv($dividend, $divisor);
echo $result; // 6.3382530011411E+29

Using the fdiv() function, we get a more accurate calculation result.

To sum up, the emergence of the fdiv() function makes it easier and more accurate for us to divide floating-point numbers. It can effectively avoid errors caused by the accuracy of computer storage of floating-point numbers and improve the efficiency of program operation. accuracy and stability.

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