An introduction to the integer type and floating-point number of the PHP data type _php Example

Syntax: integer values can be expressed in decimal, hexadecimal or octal, preceded by an optional symbol (-or +). Octal notation must be preceded by 0 (0), and hexadecimal indicates that 0x must precede the number.

$int 1=100; Decimal
$int 2=-123; Negative
$int 3=0123; Octal number
$int 4=0x1a;//Hexadecimal number

echo php_int_size//Display an integer expressed in several bytes
echo "<br/>";
echo Php_int_max;echo "<br/>";//integer maximum number (2147483647)
$fmax = 2147483648;
Var_dump (Php_int_max); a number exceeds the range of integer and will be interpreted as a float type.
echo "<br/>";
Var_dump ($fmax);

Floating-point numbers: floating-point numbers (double or real numbers)
$a = 1.34;
$b =1.8e308;
$c =8e-10;
Var_dump ($b);
The word length of the floating-point number is related to the platform, although the maximum value is 1.8e308 and has a 14-bit decimal digit precision (no more than 14 digits)
The precision is calculated from the first non-0 digits starting on the left.

such as: $a = 567.9999899//Output 567.9999899

$b = 789.8812345678543/Output 789.88123456785

$c = 0.000000008907777777/Output 0.000000008907777777

Important understanding: The precision should be calculated from the first non 0 digits starting on the left.