| author | Jaroslav Tulach <jtulach@netbeans.org> |
| Sat, 14 Jun 2008 10:04:53 +0200 | |
| changeset 210 | acf2c31e22d4 |
| parent 209 | 1c999569643b |
| permissions | -rw-r--r-- |
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package api; |
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/** Class to simplify arithmetical operations, improved version to compute |
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* the sum for ranges, but only if one uses the new constructor to indicate |
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* need for new version. |
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* |
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* @author Jaroslav Tulach <jtulach@netbeans.org> |
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* @version 2.0 |
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*/ |
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// BEGIN: design.composition.arith2.0.compat |
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public class Arithmetica {
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private final int version; |
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public Arithmetica() {
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this(1); |
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} |
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public Arithmetica(int version) {
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this.version = version; |
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} |
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public int sumTwo(int one, int second) {
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return one + second; |
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} |
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public int sumAll(int... numbers) {
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if (numbers.length == 0) {
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return 0; |
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} |
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int sum = numbers[0]; |
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for (int i = 1; i < numbers.length; i++) {
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sum = sumTwo(sum, numbers[i]); |
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} |
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return sum; |
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} |
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public int sumRange(int from, int to) {
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switch (version) {
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case 1: return sumRange1(from, to); |
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case 2: return sumRange2(from, to); |
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default: throw new IllegalStateException(); |
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} |
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} |
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private int sumRange1(int from, int to) {
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int len = to - from; |
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if (len < 0) {
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len = -len; |
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from = to; |
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} |
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int[] array = new int[len + 1]; |
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for (int i = 0; i <= len; i++) {
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array[i] = from + i; |
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} |
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return sumAll(array); |
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} |
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private int sumRange2(int from, int to) {
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return (from + to) * (Math.abs(to - from) + 1) / 2; |
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} |
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} |
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// END: design.composition.arith2.0.compat |