Difference between float and double in php?

Question

I have this code

$vad = 1.1;

print gettype($vad);

var_dump($vad);

this will output:

double
float(1.1) 

Answer 1

In PHP 7.0.14

function test(double $a) {
    var_dump($a);
}
test(2.2111);

Returns "Fatal error: Uncaught TypeError: Argument 1 passed to test() must be an instance of double, float given".

function test(float $a) {
    var_dump($a);
}
test(2.2111);

Prints 2.2111 to the screen.