## What is floor function in mathematics?

A floor function which is also known as the greatest integer function in maths takes a real number “x” as an input. It returns the greatest integer that is less than or equal to input number x. It is normally denoted as floor(x) or ⌊x⌋. It is used to convert a real number having fractional part into an integer without the fractional part. To understand it better let's have a quick look at the examples below.```
floor(5) = 5
floor (1.3) = 1
floor (7.9) = 7
```

## What is Math.floor() method in Java?

Java provides an equivalent of mathematical floor function. Here’s how you can understand it.*Math.floor() method in Java returns a “double” value equal to the greatest integer less than or equal to the argument.*

## Method Header

```
public static double floor(double x)
```

The method takes a double value (double x) as a parameter whose floor has to be determined. It does not require to import any external package.
## Return Type math.floor

The method returns a double (double floor) value which is less than or equal to the given parameter.## Example

```
public class Driver1 {
public static void main(String[] args) {
double x = 50; // floor for whole number (Integer value)
double floorValue = Math.floor(x);
System.out.println("floor⌊" + x + "⌋ = " + floorValue);
x = 21.7; // floor for positive decimal
floorValue = Math.floor(x);
System.out.println("floor⌊" + x + "⌋ = " + floorValue);
x = -21.7; // floor for negative decimal
floorValue = Math.floor(x);
System.out.println("floor⌊" + x + "⌋ = " + floorValue);
x = 0; // floor for zero (Integer value)
floorValue = Math.floor(x);
System.out.println("floor⌊" + x + "⌋ = " + floorValue);
// Boundary Cases
x = +3.3/0; // Case I - floor for +Infinity
floorValue = Math.floor(x);
System.out.println("floor⌊" + x + "⌋ = " + floorValue);
x = -3.3/0; // Case II - floor for -infinity
floorValue = Math.floor(x);
System.out.println("floor⌊" + x + "⌋ = " + floorValue);
x = -0.0/0; // Case III - floor for NaN
floorValue = Math.floor(x);
System.out.println("floor⌊" + x + "⌋ = " + floorValue);
}
}
```

### Output

floor⌊50.0⌋ = 50.0
floor⌊21.7⌋ = 21.0
floor⌊-21.7⌋ = -22.0
floor⌊0.0⌋ = 0.0
floor⌊Infinity⌋ = Infinity
floor⌊-Infinity⌋ = -Infinity
floor⌊NaN⌋ = NaN

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