double floorToDouble( )

Returns the greatest integer double value no greater than this.

If this is already an integer valued double, including -0.0, or it is not a finite value, the value is returned unmodified.

For the purpose of rounding, -0.0 is considered to be below 0.0. A number d in the range 0.0 < d < 1.0 will return 0.0.

Source

/**
 * Returns the greatest integer double value no greater than `this`.
 *
 * If this is already an integer valued double, including `-0.0`, or it is not
 * a finite value, the value is returned unmodified.
 *
 * For the purpose of rounding, `-0.0` is considered to be below `0.0`.
 * A number `d` in the range `0.0 < d < 1.0` will return `0.0`.
 */
double floorToDouble();