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# Java - Math.floor() method example

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The `Math.floor()` function returns an integer value that is smaller than or equal to the argument - the result of round down operation.

``````public class MathExample {

public static void main(String[] args) {
System.out.println( Math.floor(  5     ) ); //  5.0

System.out.println( Math.floor(  2.49  ) ); //  2.0
System.out.println( Math.floor(  2.50  ) ); //  2.0
System.out.println( Math.floor(  2.51  ) ); //  2.0

System.out.println( Math.floor( -2.49  ) ); // -3.0
System.out.println( Math.floor( -2.50  ) ); // -3.0
System.out.println( Math.floor( -2.51  ) ); // -3.0

System.out.println( Math.floor(  0.999 ) ); //  0.0
System.out.println( Math.floor(  1.001 ) ); //  1.0
System.out.println( Math.floor( -1.001 ) ); // -2.0
}
}``````

## 1. Documentation

 Syntax ``````package java.lang; public final class Math { public static double floor(double number) { ... } }`````` Note: Classes in the `java.lang` package are imported automatically, so it is not necessary to do it manually - we use just `Math.floor()` call. Parameters `number` - double value (primitive value). Result Rounded down `number` value (primitive value). If `number` value is equal to `NaN` it returns `NaN`. If `number` value is equal to `-Infinity` it returns `-Infinity`. If `number` value is equal to `+Infinity` it returns `+Infinity`. Description `floor` is a static method that takes only one parameter and returns a rounded down value.

## 2. Rounding with precision down-to `n` places example

``````public class MathExample {

static double floorPrecised(double number, int precision) {
double power = Math.pow(10, precision);

return Math.floor(number * power) / power;
}

public static void main(String[] args) {
System.out.println( floorPrecised(     5  ,  0 ) ); // 5.0
System.out.println( floorPrecised(     5. ,  0 ) ); // 5.0
System.out.println( floorPrecised(      .5,  0 ) ); // 0.0

System.out.println( floorPrecised(  1.1234,  0 ) ); // 1.0
System.out.println( floorPrecised(  1.1234,  1 ) ); // 1.1
System.out.println( floorPrecised(  1.1235,  2 ) ); // 1.12
System.out.println( floorPrecised(  1.1235,  3 ) ); // 1.123

System.out.println( floorPrecised( -1.1234,  0 ) ); // -2.0
System.out.println( floorPrecised( -1.1234,  1 ) ); // -1.2
System.out.println( floorPrecised( -1.1234,  2 ) ); // -1.13
System.out.println( floorPrecised( -1.1234,  3 ) ); // -1.124

System.out.println( floorPrecised(    1234, -1 ) ); // 1230.0
System.out.println( floorPrecised(    1234, -2 ) ); // 1200.0
System.out.println( floorPrecised(    1234, -3 ) ); // 1000.0

System.out.println( floorPrecised(  5_000.000_001,  0 ) ); // 5000.0
System.out.println( floorPrecised(  5_000.000_001,  6 ) ); // 5000.000001
System.out.println( floorPrecised(  5_000.000_001, -3 ) ); // 5000.0
}
}``````

## References

1. Floor and ceiling functions - Wikipedia

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