# compareTo method

int compareTo (num other)

Compares this to `other`.

Returns a negative number if `this` is less than `other`, zero if they are equal, and a positive number if `this` is greater than `other`.

The ordering represented by this method is a total ordering of num values. All distinct doubles are non-equal, as are all distinct integers, but integers are equal to doubles if they have the same numerical value.

For doubles, the `compareTo` operation is different from the partial ordering given by operator==, operator< and operator>. For example, IEEE doubles impose that `0.0 == -0.0` and all comparison operations on NaN return false.

This function imposes a complete ordering for doubles. When using `compareTo` the following properties hold:

- All NaN values are considered equal, and greater than any numeric value.
- -0.0 is less than 0.0 (and the integer 0), but greater than any non-zero negative value.
- Negative infinity is less than all other values and positive infinity is greater than all non-NaN values.
- All other values are compared using their numeric value.

Examples:

    print(1.compareTo(2)); // => -1
    print(2.compareTo(1)); // => 1
    print(1.compareTo(1)); // => 0

    // The following comparisons yield different results than the
    // corresponding comparison operators.
    print((-0.0).compareTo(0.0));  // => -1
    print(double.nan.compareTo(double.nan));  // => 0
    print(double.infinity.compareTo(double.nan)); // => -1

    // -0.0, and NaN comparison operators have rules imposed by the IEEE
    // standard.
    print(-0.0 == 0.0); // => true
    print(double.nan == double.nan);  // => false
    print(double.infinity < double.nan);  // => false
    print(double.nan < double.infinity);  // => false
    print(double.nan == double.infinity);  // => false

## Implementation

    int compareTo(num other);