The difference between the Ceil,floor,round,intval function of PHP's rounding function

During the development process, when you encounter the data processing to take the whole time, you will use which, small Tao to introduce: PHP take the whole function has ceil,floor,round,intval, the following detailed introduction:

1, ceil-into a method to take the whole
Description
float ceil (float $value)
Returns the next integer not less than value, in which value is entered if there is a fractional part. The type returned by Ceil () is still float, because the range of float values is usually larger than the integer.
Ceil () example

1. <?php
2. echo ceil (4.3); 5
3. echo ceil (9.999); 10
4. ?>

2, floor-to take the whole method of rounding
Description
Float Floor (float $value)
Returns the next integer not less than value, rounding out the fractional part of value. The type returned by floor () is still float, because the range of float values is usually larger than the integer.
Floor () example

1. <?php
2. echo floor (4.3); 4
3. echo Floor (9.999); 9
4. ?>

3, round-to the floating point number rounding
Description
Float round (float $val [, int $precision])
Returns the result of rounding Val based on the specified precision precision (number of digits after decimal point). Precision can also be negative or 0 (the default value).
Round () example

1. <?php
2. Echo round (3.4); 3
3. Echo round (3.5); 4
4. Echo round (3.6); 4
5. Echo Round (3.6, 0); 4
6. Echo Round (1.95583, 2); 1.96
7. Echo Round (1241757,-3); 1242000
8. Echo Round (5.045, 2); 5.05
9. Echo Round (5.055, 2); 5.06
10. ?>

note:php default does not correctly handle strings that resemble "12,300.2″."
The Note:precision parameter was introduced in PHP 4.

4. intval-gets the integer value of the variable
Description
int intval (mixed $var [, int $base])
Returns the integer value of the variable var by using a specific binary conversion (by default, decimal).
var can be any scalar type. Intval () cannot be used with an array or object.
Intval () example

1. <?php
2. echo intval (4.3); 4
3. echo intval (9.999); 9
4. ?>

Note:
The base parameter of Intval () will not be effective unless the var argument is a string.

The floor function is considered to be the same as the Intval function, which is different from one returned floating-point number (float) and the other as an integer, because the range of float values is usually larger than the integer. However, the values themselves are equal.

The difference between the Ceil,floor,round,intval function of PHP's rounding function