From c7f8f772c056f8c5a84d1fd448b5fdde1b5be1c8 Mon Sep 17 00:00:00 2001
From: Adan Rodriguez <adanrodriguezthis33@gmail.com>
Date: Wed, 30 Jan 2019 11:23:42 -0300
Subject: [PATCH] conversion decimal to hexadecimal

---
 .../com/conversions/DecimalToHexadecimal.java | 26 +++++++++++++++++++
 .../conversions/DecimalToHexadecimalTest.java | 17 ++++++++++++
 2 files changed, 43 insertions(+)
 create mode 100644 src/main/java/com/conversions/DecimalToHexadecimal.java
 create mode 100644 src/test/java/com/conversions/DecimalToHexadecimalTest.java

diff --git a/src/main/java/com/conversions/DecimalToHexadecimal.java b/src/main/java/com/conversions/DecimalToHexadecimal.java
new file mode 100644
index 00000000..e41b825d
--- /dev/null
+++ b/src/main/java/com/conversions/DecimalToHexadecimal.java
@@ -0,0 +1,26 @@
+package src.main.java.com.conversions;
+
+import java.math.BigInteger;
+
+public class DecimalToHexadecimal {
+    private static final char hexChars[] = {'0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'};
+    private static final BigInteger valueHex = new BigInteger("16");
+
+    /**
+     * This method converts and decimal number to a Hexadecimal number
+     * @param decimalStr
+     * @return hexadecimal number
+     */
+    public String decimalToHex(String decimalStr){
+        BigInteger decimal = new BigInteger(decimalStr);
+
+        int rem;
+        String hex = "";
+        while(decimal.compareTo(BigInteger.ZERO) > 0) {
+            rem = decimal.mod(valueHex).intValueExact();
+            hex = hexChars[rem] + hex;
+            decimal = decimal.divide(valueHex);
+        }
+        return hex;
+    }
+}
diff --git a/src/test/java/com/conversions/DecimalToHexadecimalTest.java b/src/test/java/com/conversions/DecimalToHexadecimalTest.java
new file mode 100644
index 00000000..6a9540eb
--- /dev/null
+++ b/src/test/java/com/conversions/DecimalToHexadecimalTest.java
@@ -0,0 +1,17 @@
+package src.test.java.com.conversions;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+public class DecimalToHexadecimalTest {
+
+    @Test
+    public void testDecimalToHexadecimalTest() {
+        DecimalToHexadecimal decimalToHexadecimal = new DecimalToHexadecimal();
+        Assert.assertEquals("Incorrect Conversion", "F", decimalToHexadecimal.decimalToHex("15"));
+        Assert.assertEquals("Incorrect Conversion", "121", decimalToHexadecimal.decimalToHex("289"));
+        Assert.assertEquals("Incorrect Conversion", "AAAAAAAAAAAAAAAAAA1", decimalToHexadecimal.decimalToHex("50371909150609548946081"));
+        Assert.assertEquals("Incorrect Conversion", "A", decimalToHexadecimal.decimalToHex("10"));
+        Assert.assertEquals("Incorrect Conversion", "8B2F", decimalToHexadecimal.decimalToHex("35631"));
+    }
+}
\ No newline at end of file