Move the source files into a new default directory.

src/main/java/org/nwapw/abacus/number/NumberInterface.java

@@ -0,0 +1,77 @@
+package org.nwapw.abacus.number;
+
+/**
+ * An interface used to represent a number.
+ */
+public interface NumberInterface {
+
+    /**
+     * The maximum precision to which this number operates.
+     * @return the precision.
+     */
+    int getMaxPrecision();
+
+    /**
+     * Multiplies this number by another, returning
+     * a new number instance.
+     * @param multiplier the multiplier
+     * @return the result of the multiplication.
+     */
+    NumberInterface multiply(NumberInterface multiplier);
+    /**
+     * Divides this number by another, returning
+     * a new number instance.
+     * @param divisor the divisor
+     * @return the result of the division.
+     */
+    NumberInterface divide(NumberInterface divisor);
+    /**
+     * Adds this number to another, returning
+     * a new number instance.
+     * @param summand the summand
+     * @return the result of the summation.
+     */
+    NumberInterface add(NumberInterface summand);
+    /**
+     * Subtracts another number from this number,
+     * a new number instance.
+     * @param subtrahend the subtrahend.
+     * @return the result of the subtraction.
+     */
+    NumberInterface subtract(NumberInterface subtrahend);
+
+    /**
+     * Returns a new instance of this number with
+     * the sign flipped.
+     * @return the new instance.
+     */
+    NumberInterface negate();
+
+    /**
+     * Raises this number to an integer power.
+     * @param exponent the exponent to which to take the number.
+     * @return the resulting value.
+     */
+    NumberInterface intPow(int exponent);
+
+    /**
+     * Compares this number to another.
+     * @param number the number to compare to.
+     * @return same as Integer.compare();
+     */
+    int compareTo(NumberInterface number);
+
+    /**
+     * Same as Math.signum().
+     * @return 1 if this number is positive, -1 if this number is negative, 0 if this number is 0.
+     */
+    int signum();
+
+    /**
+     * Promotes this class to another number class.
+     * @param toClass the class to promote to.
+     * @return the resulting new instance.
+     */
+    NumberInterface promoteTo(Class<? extends NumberInterface> toClass);
+
+}